Tuesday 11 November 2014

AE1005 WIIND TUNNEL TECHNIQUES Questions Bank 2014



AE1005 WIIND TUNNEL TECHNIQUES Questions Bank 2014

Anna University, Chennai

Anna_University,_Chennai_logo

SRINIVASAN ENGIEERING COLLEGE DEPARTMENT OF AERONAUTICAL ENGINEERING AE1005 WIIND TUNNEL TECHNIQUES

QUESTION BANK (PAR T – B)

UNIT - 1

1. Explain Buckingham PI theorem with example.

2. Define any five non dimensionless members.

3. An aircraft is to fly at a height –

C for completes dynamic similarity. What would be P & V should be used

WT F μα T (T + 7), E = γ , P = ρRT T v γ

of specific heats.

4. A 7.2m height & 15m long spillway discharges 94m3/s discharge under a head of 2.0m.

If 1:9 scale model of this spillway is to be constructed, determine model dimensions, head o ver spillway model & the model discharge. If model experience a force of 7500N.

Determine force on the prototype.


UNIT - 2

5. Explain about losses in subsonic wind tunnel.

6. Give the C lassification of wind tunnel & explain about hypersonic wind tunnel.

7. With a neat sketch explain about types of supersonic wind tunnel.

8. Explain about losses in supersonic wind tunnel.

9. Explain about high speed wind tunnel with neat sketch.


UNIT – 3

10. Derive the expression for test section speed.

11. With a neat sketch explain about calibrations of supersonic wind tunnel.

12. Explain about flow angularity measurements & its types.

13. With a neat sketch explain about turbulence measurements.


UNIT – 4

14. Explain about any one types of wind tunnel balances with neat example.

15. With a neat sketch explain about velocity measurements using LDA.

16. With a neat sketch brief about pressure measurements by using transducers.

17. With a neat sketch explain about force measurements in wind tunnel.


UNIT – 5

18. Explain about optical method of flow visualization.

19. Explain flow visualization method by using smoke & tuft grid techniques.

20. With a neat sketch explain about dye injection techniques.

AE1005-WIND TUNNEL TECHNIQUES Questions Bank 2014



AE1005-WIND TUNNEL TECHNIQUES Questions Bank 2014

Anna University, Chennai

Anna_University,_Chennai_logo

PART -B

UNIT I

1. Derive on the basis of dimensional analysis suitable parameters to present the thrust developed by a propeller. Assume that the thrust depends on the angular velocity, speed of advance, diameter dynamic viscosity, mass density, and elasticity of the fluid medium which can be denoted by the speed of sound in the medium?

2. The pressure difference in a pipe of diameter and length due to viscous flow depends on the velocity viscosity and density .using Buckingham theorem obtains an expression

3. Explain Buckingham pi theorem with example

4. Briefly explain the types non dimensionless number

UNIT II

1. Derive the pressure drop coefficient for diffuser and effuse and draw the corresponding curve?

2. Explain the operation, merits, demerits and application of hypersonic wind tunnel and also briefly explain the losses in subsonic wind tunnel.

3. Explain the operation, merits, demerits and application of supersonic and aero acoustic tunnel?

4. Explain the operation, merits, demerits and application of any three special purpose wind tunnels

5. Briefly explain the special purpose hypersonic wind tunnel


UNIT III

1. Derive the equation for test section speed in low speed wind tunnel and draw the corresponding curve

2. Explain types of flow angularity measurement.

3. Explain types of turbulence measurement in wind tunnel?

4. Explain the operation Gun tunnel and Shock tunnel

5. With a neat illustration explain the objective of calibration of a wind tunnel. In what way the calibration procedure for a supersonic tunnel different from that of a subsonic wind tunnel?


UNIT IV

1. How to measure velocity of flow using LDA technique

2. Explain wire type balance with neat sketch and mention the merits and demerits

3. Explain strut type balance with neat sketch and mention the merits and demerits

4. Explain six component balance with neat sketch

5. Mention the features and characteristics of wind tunnel balance


UNIT V

1. Explain the classification of flow visualization techniques

2. Explain the optical flow visualization techniques

3. Explain surface flow visualization technique

4. Explain the data flow visualization techniques

AE1005-WIND TUNNEL TECHNIQUES Two Marks Questions With Answers 2014



AE1005-WIND TUNNEL TECHNIQUES Two Marks Questions With Answers 2014

Anna University, Chennai

Anna_University,_Chennai_logo

SRINIVASAN ENGINEERING COLLEGE DEPARTMENT OF AERONAUTICAL ENGINEERING AE1005-WIND TUNNEL TECHNIQUES

Two Mark Questions

UNIT-1

1. DEF INE MACH NUMBER?

It's defined as the square root of the ratio of the inertia force of a flowing fluid

to the elastic force.

2. DEF INE REYNOLDS NO?

It's defined as the ratio of an inertia force of the flowing fluid and the viscous force of the fluid

3. DEF INE EULER'S NO?

It's defined as the square root of the ratio of the inertia force of a flowing fluid

to the pressure force

4. DEF INE WEBER'S NO?

It's defined as the square root of the ratio of the inertia force of a flowing fluid to surface tension force

5. DEF INE F ROUDE'S NO?

It's defined as the square root of the ratio of the inertia force of a flowing fluid

to the gravity force

6. DEF INE BUCKINGHAMS Л THEOREM?

If there are n variables in a physical phenomenon and if this variables contain m fundamental dimension (M, L, T) then the variables are arranged to (n- m) dimensionless terms, each term is called л-term

7. WHAT IS MEANT BY S IMILARITIES?

Model and prototype have similar properties or model and prototype are similar

8. WRITE DOWN THE TYP ES OF SIMILARITIES?

Ø Geometric similarity

Ø Kinematic similarity

Ø Dynamic similarity


UNIT-2

1. WHAT ARE THE C LASSIF ICATIONS OF WIND TUNNEL?

Ø Low speed wind tunnel,

Ø High speed wind tunnel,

Ø Special type tunnel.

2. WHAT IS F UNCTION OF EFFUSER?

It converts available pressure energy into kinetic energy and its located upstream of the test section.

3. WHAT IS F UNCTION OF DIFFUS ER?

It converts the kinetic energy to pressure energy and it's downstream of the test section.

4. WHAT IS BREATHER?

It is attached with an one way valve so that it take the air and by propeller suction, flow is maintained inside the return type.

5. WHAT ARE THE MERITS AN D DEMERITS OF OPEN CIRCUIT?

§ Construction cost less,

§ It no surging problem is open to the free atm. DEMERITS.

§ Tunnels much noisy,

§ Make cost environment problem.

6. DEF INE ENERGY RATIO.

It is defined as the ratio between the total kinetic energy of the flow to the energy loss.

ER = 1/K0

7. WHAT ARE THE ADVAN TAGES OF BLOW DOWN TYP E WIN D TUNNEL?

§ This is the simplest among the supersonic tunnel and most economic to build.

§ Constant blowing press can be maintaining for considerable running by throttle valve.

8. WHAT ARE THE APPLICATION OF VERTICAL WIND TUNNEL?

Ø It is used to study the spinning motion of the aircraft,

Ø Ejection of pilots from seats,

Ø Parachute flying,

Ø Helicopter operation.

9. WHAT ARE THE LOSSES IN SUP ERSONIC TUNNEL?

ü Friction losses,

ü Expansion losses,

ü Losses in the contraction cone and test section,

ü Losses in guide vanes,

ü Losses in cooling system.


UNIT – 3.

1. WHAT ARE THE TYP ES OF FLOW AN GULARITIES?

· Sphere type yaw meter,

· Claw type yaw meter.

2. WHAT ARE THE TURBULENT MEASUREMENTS?

Ø Turbulence sphere,

Ø Pressure sphere,

Ø Hot wire anemometer.

3. WHAT ARE THE METHO DS TO REDUC E TURBULENCE INSIDE W/T.

§ Using max. no of fan blades,

§ Using a very long and gradual nacelle,

§ Anti swirl vanes,

§ Providing max. Possible distance between propellers and test section.

4. PRINCIPLE OF HOT WIRE ANEMOMETER.

The rate of heat from an electrical heated wire and placed in an airstream is proportional to the velocity.


UNIT-4

1. DEF INE WIND TUNNEL BALANCE?

Wind tunnel balance is a device to measure the actual forces &moments acting on a model placed in the test section stream

2. WHAT ARE THE C LASSIF ICATIONS OF WIND TUNNEL BALANCE?

· Wire type balance

· Strut type balance

· Platform type balance

· Yoke type balance

· Strain gauge type balance

3. WHAT DO YOU MEAN BY WIRE BALANCE?

In wire type wind tunnel balances only wires are used to support the model. All the load components are transmitted to the measuring device by these wires.

4. WHAT ARE THE C LASSIF ICATIONS OF STRUT TYP E BALANCES?

· Yoke type

· Platform type

· Pyramid type

5. WHAT ARE THE TYP ES OF STRAIN GAUGE BALANCE?

· Internal balance

· Semi internal balance

· External balance

6. WHAT IS THE P RINCIP LE OF LIQUID MANOMETER?

The principle is that the pressure is balanced by the weight of a liquid column.

7. WHAT ARE THE TYP ES OF BAROMETERS?

· Syphon barometer

· Fortin barometer

· Aneroid barometer

8. GIVE SOME DISADVANTAGES OF DIAL TYP E PRESSURE GAUGE?

· They must be calibrated periodically to ensure that they continue to read correctly

· The manometers are less expensive when there is a large number of pressures to be read

· Like manometers, they cannot be easily read electronically

9. WHAT ARE THE TYP ES OF PRESSURE TRANSDUC ERS?

They are classified as mechanical, electrical & optical type

10. LIS T OUT SOME ADVAN TAGES OF PRESS URE TRANSDUCERS?

· They provide signal proportional to the applied pressure which can be automatically recorded by acquisition system

· They are relatively low volume devices & consequently respond more rapidly to pressure changes

· They are small enough to be mounted inside wind tunnel models

11. STATE THE PRINCIPLE OF LDA?

The principle is that a moving particle illuminated by a light beam scatters light at a frequency different from that of the original beam. This difference in frequency is known as Doppler shift & it's proportional to the velocity of the particle.

12. WHAT ARE THE SCATTERING SUBS TANCES USED FOR LDA?

· Micro polythene spheres

· Diluted milk droplets

· Diluted smoke particles

· Aerosol

· Fine alumina powder

13. WHAT ARE THE ADVAN TAGES OF LDA?

· It has high frequency response

· It has negligible probe interference

· It is applicable to a wide range of applications

· The measurement with LDA is absolute, linear with velocity & require no pre- calibration

14. GIVE S HORT NOTES ON REF ERENCE BEAM S YSTEM?

In reference beam system the scattered beam of light is optically mixed with original beam & the difference is obtained as the Doppler shift in frequency. This technique is known as heterodyning & it's the characteristic of a photo multiplier.

15. WHAT IS THE ADVANTAGE OF VORTEX S HEDDING TECHNIQUE?

It is capable of measuring low speeds of air which cannot be measured accurately with a conventional manometer.


UNIT-5

1. DEFINE PATHLINE?

The path of a point or particle convected with the flow is called a path line. If we could release a tracer particle at any selected point and record its subsequent path, this would be a path line.

2. DEFINE S TREAKLINE?

It is a curve which represents the instantaneous motion of the fluid particle from the given point.

3. DEFINE S TREAMLINE?

A streamline through a point at an instant in time is the line whose tangent is the velocity at that point and that follows a path through the fluid such that the tangent at every point is the local instantaneous velocity.

4. DEFINE TIMELINE?

A timeline is generated by simultaneously emitting a short burst of tracers along a line perpendicular to the local flow. This marks a line of elements that are in a straight line at the initial time.

5. HOW CAN WE CLASSIFY FLOW VIS UALIS ATION?

The flow visualization can be broadly classified into two, they are

ü surface flow visualization

ü flow field visualization

6. WHAT ARE THE KEY AS PECTS OF SURFACE FLOW THAT CAN BE INVES TIGATED FROM SURFACE FLOW VISUALISATION?

Key aspects of surface flows that may be investigated using visualization techniques

include

ü Stagnation point location

ü Separation lines

ü Location of boundary layer transition

ü Characteristic unsteadiness

ü Extent of separation zones

ü Types of critical points

7. WHAT ARE THE R EQUIREMENTS OF TUFTS?

The Tufts must be of light, flexible material that will align itself with the local surface flow as a result of direct of direct aerodynamic force.

8. WHAT ARE THE MATERIALS USED FOR MAKING TUFTS?

The most commonly used material is light yarn with weights and lengths chosen according to model size and test speed.

9. WHAT ARE THE MATERIALS USED FOR MAKING MINITUFTS?

The tuft material is monofilament nylo n that has been treated with a fluorescent dye.

10. WHAT AR E THE ADVANTAGES OF USING TUFTS?

ü Easily producible

ü Once the tufts are installed the model can be repositioned and indications studied visually & photographed for as long as desired.

11. WHAT AR E THE METHODS OF OPTICAL FLOW VISUALISATION?

ü Shadow graph

ü Schlieren technique

ü Interferometer

12. WHAT AR E THE APPLICATION OF SMOKE VISUALISATION?

Ø Flow over an aerofoil

Ø Study vortex motion

13. WHAT AR E THE ADVANTAGES OF OPTICAL TECHNIQUES?

Ø Non intrusive

Ø Avoiding the formation of unwanted shockwaves

Ø Avoid problems associated with the introduction of foreign particles

14. WHAT IS THE FUNDAMENTAL PRINCIPLE OF THE INTERFEROMETER?

From corpuscular properties of light, we know that when light travels through a gas the velocity of propagation is affected by the physical properties of the gas.

C=fλ

15. WHAT IS THE FUNDAMENTAL PRINCIPLE OF S CHLIEREN TECHNIQUE?

The speed of a wave front of light varies inversely with the inde x of refraction of the medium through which the light travels.

AE2352 EXPERIMENTAL STRESS Questions Bank 2014



AE2352 EXPERIMENTAL STRESS Questions Bank 2014

Anna University, Chennai

Anna_University,_Chennai_logo

PART –B AE2352EXPERIMENTAL STRESS ANALYSIS

Unit -1

1. Explain the basic generalized measuring system with neat sketch.

2. Describe the direct reading and null balance methods in strain measurement.

3. Explain the measurement of pressure with diagram

4. (a)Active and passive instruments

(b)Null type and deflection type instruments (c)Analogue and digital instruments (d)Tolerance and dead space

5. Explain the various elements of a measurement system with a block diagram.

6. Briefly explain static characteristic of measurement.

7. Explain briefly Errors in measurement.

8. Briefly Explain Un-Bonded and Bonded Electrical strain gauges.

9. Explain briefly Optical Extensometers.

10. Explain briefly Huggenberger and Johnson Extensometers.

11. Explain briefly choice of selection of right extensometer for material testing

12. Briefly explain the working principle of LVDT.

13. Explain with neat sketches the working of a Mechanical extensometer.

14. Explain with neat sketches the working of a Electrical extensometer.

15. Explain with neat sketches the working of an acoustical extensometer.

16. What are the different types of strain gauges? What are the advantages over other types of gauges?

Why foil type gauges are prepared over wire type of gauges?

17. What are the basic characteristics of a strain gauge? Which factors should be considered while selecting a strain gauge?


Unit -1I

1. Derive the expression for balanced and un-balanced Wheatstone bridge circuit

2. Derive the expression for principal strains and its direction in terms of strain measured in a three element rectangular rosette (gauge A along x- axis, gauge B along 450 to the x- axis and gauge C along y- axis).

3. Derive an expression for output voltage of Wheatstone bridge circuit for strain measurements.

4. Derive an expression for output voltage of Potentiometer circuit for strain gauges.

5. Determine principal stresses and principal strains with help of a delta rosette mounted on an aluminum specimen with values of A = 400µ , B = 400µ , C= 400µ , Eal = 70GPa, γ = 0.3

6. Three strain gauges are applied to an area at a point in such a manner that gauge 'b' makes a positive

angle of 300 with gauge 'a' and gauge 'c' makes a positive angle of 450 with gauge 'b' . The strain readings obtained from the gauges are as follows.

Gauge Strain µ m/m a -600

b 300 c 400

Calculate the principal strains, principal stresses and principal directions.

7. Derive the expression for principal strains and its direction in terms of strain measured in a Four element rectangular rosette

8. Derive the expression for principal strains and its direction in terms of strain measured in a Delta rosette

9. Explain briefly the NULL balance bridges.


Unit-III

1. Explain the effects of stressed model in a plane polariscope in dark-field set up.

2. What is meant by compensation in photo elasticity and explain any two fringe compensation method in detail with its advantages over other methods.

3. Explain the importance of isoclinic's and isochromatic with neat sketch.

4. Explain the separation technique based on the equilibrium equation.

5. Explain two separation technique used in photoelasticity.

6. Explain fringe sharpening and fringe multiplication techniques used in photo elasticity.

7. Derive the expression for the intensity of emerging light from a plane polariscope with a stressed model and show how it enables us to determine the isoclinics and the isochromatics.

8. Show the intensity of light emerging from circular polariscope is a function of principal stress difference.

9. Derive the relation between the stresses, relative retardation, material fringe value and thickness of

photoelastic model.


Unit IV

1. Explain the moiré method in brief and discuss the fundamental properties of the moiré fringes. .

2. Explain briefly the Moiré method of strain analysis.

3. Explain Brittle coating technique with neat sketch.

4. Explain working principle of Holography

5. Enumerate the brittle coating crack pattern with explanation.

1. Explain and application of the followings: (i) Radiography

(ii) Ultrasonic testing

2. Explain:

(i) Moiré method of strain analysis. (ii) Acoustic emission technique.

3. Explain \

(i) Eddy current testing

(ii) Brittle coating technique


Unit V

4. Explain the working principle of Fibre optic sensors with neat sketch.

5. Explain holography and ultrasonic C-scan non-destructive testing methods with its application.

6. Explain acoustic emission technique with neat sketch.

7. Explain radiography and fluorescent penetrant

8. What is the principles of radiography and explain the production of X-rays with the help of schematic diagram.

Monday 10 November 2014

AE-2352 Experimental Stress Analysis Two Marks Questions With Answers 2014



AE-2352 Experimental Stress Analysis Two Marks Questions With Answers 2014

Anna University, Chennai

Anna_University,_Chennai_logo

SRINIVASAN ENGINEERING COLLEGE DEPARTMENT OF AERONAUTICAL ENGINEERING

AE-2352 Experimental Stress Analysis

Two Mark Questions

Unit I

1. Define Measurement:

The measurement of a given quantity is essentially an act or result of comparison between a quantity whose magnitude (amount) is unknown, with a similar quantity whose magnitude (amount) is known, the later quantity being called a standard.

2. What are the basic requirements for measurement?

(i) The standard used for comparison purposes must be accurately defined & should be commonly acceptable.

(ii) The standard must be of the same character as the measure and (ie, the

unknown quantity or the quantity under measurement)

(iii) The apparatus used and the method accepted for the purposes of comparison must be provable.

3. What are the methods of measurements?

(i) Direct Method: In these methods, MEASURAND is directly compared against a STANDARD.

(ii) Indirect Method: Measuring systems are used in indirect methods for measurement purposes

4. What is dimensional measurement?

Dimensional Measurements are characterized as determination of size of an object. These are the measurements of dimensions of an object.

5. What are the 'STANDARD'S for the measurement of an angle?

The primary standards of angle may be taken either as angle subtended by a circle at its centre ie, 360° or as angle between two straight line intersecting in a manner such that all four angles so formed are equal, ie, each angle is 90°

6. How we can measure the Area of survey plats?

Measurement of area of regular and standard geometrical figures can be obtained from the dimensions using standard mathematical relationships.

There are many engineering applications which require the measurement of plane area. Graphical determination of the area of survey plots form maps, the integration of function to determine the area enclosed by a curve analysis of experimental data may require the use of measurement of plane area.

7. Give any two methods for measure an unknown force

An unknown force may be measured by the following methods,

1. Balancing the unknown force against the known gravitational force either directly

(or) indirectly using a system of levers.

2. Transferring the unknown force to a fluid pressure and then meaning the resulting fluid pressure. Hydraulic and Pneumatic load cells are used for transferring

the force into pressure.

8. How we can measure the temperature changes?

Temperature is not measured directly, but is measured through indirect means; change of temperature of a substance causes a variety of effects. These effects may be physical, chemical, electrical (or) optical and they may be used for the measurement of temperature through use of proper temperature sensing devices.

9. Tell some thing about 'static characteristics' and 'static calibration' in measurements:

'Static characteristics' of a measurement system are in general those that must

be considered when the system or instrument is used to measure a condition not varying with time. All the static performance characteristics are obtained in one form or another by a process called' static calibration'

10. What is accuracy and tell about point accuracy?

Accuracy is the closeness with which an instrument reading approaches the true value of the quantity being measured. Thus accuracy of a measurement means conformity to truth.

'Point Accuracy' is the accuracy of the instrument only at one point on it scale.

11. Give the Type of errors in measurements

(i) Gross errors (ii) Random rrors (iii) systematic errors

- Instrumental errors

- Environmental errors

- Observational errors

12. Differentiate Gross error and Instrumental Error

Gross errors mainly cover human mistakes in reading instruments and recording and calculating measurement results.

Instrumental Error occurs due to the wrong adjustments of a measuring devices while it construction or misalignments of its pats.

13. Differentiate environmental and systematic errors

Environmental errors causes due to the surrounding condition of instruments, but systematic errors causes because of the fault of the arrangement of measuring system during the whole measuring process.

14. What absolute static error? Give example

Absolute static error is the difference between measured values of quantity and the true value of quantity. ie, Eo= X(m) - X(t)

Example: an error of 2mm is negligible when the length being measured is of the

order of ( 1000 mm) 1 m but the same error of 12 mm may be considerable when the measurement of 10mm length.

15. What do you mean by limiting errors?

The limits of the deviations from the specified values of measurement datas are defined as `Limiting errors' (or) `Guarantee error'

16. Determine relative limiting error:

The relative error (fractional error) is defined as the ratio of the error to the specified magnitude (nominal magnitude) of a quantity.

Relative limiting error A Limiting error

( Er) = =

As A Normal Value

17. What is an uncertainty in a measurement?

Un certainty of measurement is a parameter associated with the result of measurement, that characterizes the dispersion of values that could be reasonably attributed to the measurand.

18.Define static sensitivity

the static sensitivity of an instrument or an instrumentation system is the ratio of the magnitude of the output quantity to the magnitude of input )quantity being measured)

19. Define scale range:

The scale range of an instrument is defined as the difference between the largest and the smallest reading of the instruments.

20. What is the frequency range in measurements?

Frequency range is defined as frequency over which measurements can be performed with a specified degree of accuracy.

21. What is extensometer?

Extensometer is an instrument used top measure minute deformation of material while it is subjected to a stress.

22. Classify the extensometers depending upon the magnification systems.

1. Mechanical Extensometers

2. Optical extensometers

3. Acoustical (Vibrating wire) extensometers

4. Electrical extensometers

5. Pneumatic extensometers.

23. What are the Basic Requirements of extensometer?

1. Very high magnification:The magnification required is usually greater than 1000: 1

2. Sensitivity: The relation between input and output should not be affected by the reversal in the direction of input and this requires that the movement should not have any friction.

3. Low input force: The input force required to cause displacement should be extremely small thus there is no defamation of the component due to the process of measurement.

24. Classify the mechanical extensometers depending upon the manner of obtaining the magnification.

1. Wedge magnification

2. Screw magnification

3. Compound magnification

4. Lever magnification

25. Give the disadvantages of a simple mechanical lever magnification

For strain measurements on inner surfaces of small structures, the clearance may be in sufficient for the gauge and all its auxiliary equipment.

26. Give the magnification capacity & gaugelength of Huggen-Berger tensometer

The magnification may vary from 300 to 2000 depending upon the model. The gauge length varies from 12.5 to 25 mm.

27. Give the advantages of scratch gauge

1. Compact in size

2. It can be attached to almost any surface with clamps or screws & adhesive bonding

3. It can measure scratch under all types of loading (static, shock, fatigue)

4. It can be used to record stress in all types of environments.

28. Tell something about the magnification capacity of Marten's extensometer

This instrument is extremely sensitive and by using telescope, regarding may be estimated to 1/10 mm which corresponding to a length charge of approximately 0.0002m.

29. Give the classifications of Electrical strain gauges

(a) inductance (or) magnetic strain gauges

(b) Electrical resistance strain gauges

(c) The capacitance strain gauges.

30. How strain can be measured by using Electrical strain gauges?

Electrical strain gauge is a device in which a change in length produces a change in some electrical characteristics of the gauges.

31. Give the working principle of inductance strain gauges?

An electrical inductance gauge is a device in which the mechanical quantity to be measured produced a change in the magnetic field, and hence in the impedance of a current carrying coil.

32. Give the working principle of eddy- current gauges

In this types of gauges the losses in the magnetic circuit are varied by changing the thickness or position of the high- loss element inserted in the magnetic field.

33. What is known as foil strain gauges?

The foil strain gauge has metal foil photo- etched in a grid pattern of the electric insulator of the thin resin and gauge leads attached.

34. What is the basic principle of unbonded metallic strain gauges

the principle of unbonded metallic gauges is based on change in electrical resistance of a metallic wire due to change in tension of the wire.


Unit -II

1. What is photo-etching?

Photo etching is the act of producing grid configuration on metal foil with the help of photo effect.

2. What is known as strip gauges?

The number of strain gauges are arranged in a particular manner is called strip gauges.

3. What is known as strain rosettes?

An arrangement of strain gauges in particular orientation or angle is known as strain rosettes

4. Give the quantities required for a good gauge material?

High gauge factor High resistance Low temperature

sensitivity

High electrical stability Good corrosion resistance

High yield point stability

5. Give some arrangements of strain gauges to obtain strain rosettes

1. Two gauge rosette

2. Rectangular rosette

a) Three element b) Four element

3. Delta (or) Equiangular rosette

4. T. Delta rosette

6. What are the methods are available for computing the strain rosette datas?

1. Analytical Solutions

2. Graphical Solutions

3. Semi ± graphical (or) vectorial layout method

4. Nomographic Solutions

5. Geometrical Computers.

7. Give the advantages of strain Rosette analysis.

(i)Extreme simplicity and speed of application. (ii)Possibility of allowing for transverse effects. (iii)No requirements for additional equipments.

(iv) The possibility of training relativity unskilled persons to use the method.

8.Give the type of strain gauge circuits.

1. Wheat stone bridge circuits for static strain measurements.

2. Potentiometer circuits for dynamic strain measurements.

9. Define sensitivity of potentiometer:

Sensitivity of the potentiometer circuit is defined as the ratio of the output voltage divided by the strain.

1. Define Light


UNIT III

Light is usually defined as the radiation that can affect the human eye.

2. Define White light:

Light from a source that emits a continuous spectrum with equal energy for every wave length is called white light.

3. Define monochromatic light:

Light of a single wave length is called monochromatic light. Example: sodium vapour lamp, Hg arc lamp.

4. What is wave front?

The focus of points on different radial lines from the source exhibiting the same disturbance at a given instant of time, in a surface known as a wave front.

5. Define Ray?

A line normal to the wave front, indicating the direction of propagation of the waves is called a ray.

6. What are longitudinal waves?

The waves in which vibration are along the direction of their travel is known as longitudinal waves.

7. What are transverse waves?

Transverse waves are waves in which vibrations are perpendicular to the direction of wave travels.

8. What is polarized light?

The light having vibration only along a single straight line perpendicular to the direction of propagation of light is said to be polarized.

9. What is plane of polarization?

The plane containing the direction of propogation of light, but containing no vibrations is called the plane of polarization.

10. What are the methods are available to obtain plane polarized light?

(i) Refraction and Reflection for glass plate. (ii) By using Nichol Prism.

11. What are the disadvantages are available in Nichol prism when we use that to obtain plane polarized light?

1. Costly

2. Intensity is Poor.

12. What is the basic principle for photo elasticity?

When polarized light enters a loaded transparent component, it is split into two beams both beams travel along the same path, but each vibrates along a principal direction and travels at a speed proportional to the associated principal stress.

13. What is Refractive index?

The ratio of the velocity of light In air to the velocity in the medium is called the refractive index of the medium and is denoted by `n' .

14. What do you mean by Polariscope?

Polariscope is an optical instrument that utilizes the properties of polarized light in its operation.

15. Give the types of polariscopes used in experimental stress analysis? (i) Plane Polariscope

(ii) Circular Polariscope

16. Give the four different possible setups in circular polariscope?

Setup

Polariser- Analyzer

Quarter wave plates

Field

1

Crossed

Parallel

Bright

2

Crossed

Crossed

Dark

3

Parallel

Crossed

Bright

4

Parallel

Parallel

Dark

17. What is known as isotropic point in a polariscope setup?

In a particular point in a stressed model where σ1= σ2 , that fringe order is zero and permanent block dots appear at these points such are called isotropic points.

18. What are the properties of photo elastic materials?

1. Transparent to light used in the Polariscope.

2. Easily machinable by conventional means.

3. It should be force form residual stresses

4.They should have both mechanical and optical isotropy and homogeneity.

19. Give the most commonly used methods for compensation techniques

1. Babinet compensation method.

2. Babinet soleil compensation method

3. Tension or compression stop method.

4. Tardy method of compensation.

5. Senarment method of compensation

6. Photometric method.

20. What are the techniques used to determine the stresses at the inner layers of the body in 3D photo elasticity?

1. Locking in the stresses in the model

2. Multilayer reflection technique.


Unit - IV

1. Define Non - destructive testing

Non ±destructive testing is a technique for revealing flaws and defects in a material or device without damaging as destroying the test sample.

2. Give some advantages of NDT:

1. Can be done directly on production items without regards to part cost or quantity available.

2. Can be done on 100% of production of on representative samples.

3. Give the limitations of NDT:

1. Results often must be interpreted by a skilled. Experienced technician.

2. In absence of contact with each other, different observers may disagree on meaning & significance of test results.

4. Give the advantages of Radiographic inspection.

- The ability to detect internal flows

- An ability to detect significant variations in composition.

- Permanent recording of raw inspection datas.

5. Give some advantages of Brittle coating method.

- Provides nearly whole field area

- Is non destructive if the coating is sensitive enough.

- Is simple to analyze

6. Give some advantages by using fiber optic sensors.

- Light weight (very small in size)

- Low power requirement

- Resistant to electromagnetic interference

- High sensitivity

Saturday 8 November 2014

MG2351 PRINCIPLES OF MANAGEMENT Questions Bank 2014



MG2351 PRINCIPLES OF MANAGEMENT Questions Bank 2014

Anna University, Chennai

Anna_University,_Chennai_logo

SRINIVASAN ENGINEERING COLLEGE, PERAMBALUR

DEPARTMENT OF AERONAUTICAL ENGINEERING MG2351 PRINCIPLES OF MANAGEMENT QUESTION BANK- PART- B

UNIT-I

1. Describe the role of Managers

2. What are the historical inputs for management?

3. What are the difference between Management and Administration?

4. In today's context explain in detail the different functions of management

5. Elucidate the strategies for international business

6. What are contributions of F.W.Taylor?

7. Draw out clearly whether Management is Science or Art.

8. Discuss in detail about Henri Fayols contribution towards principles of management


UNIT-II

9. Explain the decision making process & its techniques.

10. What are the principles of formulating policies in modern organizations? Explain the essentials of formulating polices.

11. What are the various steps in planning? Discuss the considerations for planning process?

12. What are the modern techniques used in planning process?

13. State the various process of MBO.

14. Describe the formal & informal Organizations.

15. Explain the nature and purpose of organization

16. What are the various types of Plans?


UNIT-III

17. What are the various types of organization? Discuss the merits and demerits of various organizational structures?

18. Explain the nature and purpose of Organizing

19. What are the difference between centralization and decentralization?

20. What are the steps involved in selection process?.

21. Describe the various types of training

22. Explain in detail about the performance appraisal.


UNIT-IV

23. Explain various theories of motivation?

24. Explain the different form of motivation technique.

25. Explain various types of leadership?

26. Explain the process of Communication.

27. Elucidate the barriers in Communication.

28. Describe in detail about the organization culture

29. Explain in detail about the creativity and innovation


UNIT-V

30. What are the various methods of control techniques?

31. Explain in detail about the maintenance control and Quality control

32. Describe the process of controlling

33. Explain the various types of control

34. Explain in detail about the cost control and purchase control

35. Describe the importance of controlling.

MG2351 PRINCIPLES OF MANAGEMENT Two Marks Questions With Answers 2014



MG2351 PRINCIPLES OF MANAGEMENT Two Marks Questions With Answers 2014

Anna University, Chennai

Anna_University,_Chennai_logo

SRINIVASAN ENGINEERING COLLEGE, PERAMBALUR

DEPARTMENT OF AERONAUTICAL ENGINEERING MG2351 PRINCIPLES OF MANAGEMENT

TWO MARKS- PART- A

UNIT-I

1.Management

"Management is the process of designing and maintaining an environment in which individuals, working together in groups accomplish their aims effectively and efficiently"

"Art of getting things done through others"

A process of Planning, Organizing, Staffing, Leading and Controlling.

2. Characteristics of management:

Ø Management is goal oriented ( Mean to achieve goals)

Ø Management is universal ( Suitable for all Size of organizations & Activities

Ø Integrative force: Individual efforts à Converged in to organizational goals

Ø Management is a social process: Done by people, through people for people

Ø Management is a multidisciplinary: Depends on knowledge from several disciplines.

3. Objectives of management

Ø Organizational objectives: ROI, Survival and solvency of business, Growth, Goodwill and Market standing

Ø Personal objectives: Salary & Remuneration, Working conditions, Training &

development opportunities, Participation in management, Security of service.

4. Need & Importance of management

Ø To achieve Objectives & Goals

Ø Optimum utilization of resources

Ø Minimization of cost

5. Division of work: Every employee is assigned one particular work type

Authority and responsibility: Power & Commitment

6. Discipline: Rules, orders, instructions should be followed without any deviation or Choice.

7. Unity of command: One should get orders from only one superior.

8. Unity of direction: all activities should be focused towards common goals.

Subordination of Individual interest to general Interest: Adhering to Goals of organization.

9. Remuneration: Fair and reasonable payment to the contributions made

10. Centralization: Power 78 Authority sharing between Top level, Middle level & Bottom level and also across various functional divisions & Branches.

11. Scalar Chain: Un broken line of command from top to bottom level (G.M à DGM à

Managerà Asst. Managerà Supervisorà Senior employee à Skilled employee à Employee)

12. Order: Smooth flow of work and resource handling

13. Equity: Treat all employees with Justice, Similar way and Kindness

Stability of tenure of personnel: Job security

14. Initiative: Willingness to do things and also in a creative way

15. Esprit- de – corps: Team spirit and working in harmony

16. Contributions by Max weber – Bureaucratic organization:

Bureaucratic model is more efficient form of organization because it aims at high degree of precision efficiency, objectivity and rationality.

Characteristics of Weber model:

Ø Division of labour: Specialization

Ø Hierarchy of authority: Position and relationship with superiors & subordinates

Ø Rigidity in compliance with procedures and framework of rules: No deviation

Ø Impersonality: Formal and functional relationship

Ø Technical competence: Job requirements and skills

17. Behavioral approach (Neo Classical theory) Contributions of Hawthorne studies

George Elton Mayo conducted it

Conducted at Hawthorne plant of Western electronic company

1927 to 1932

Experiments conducted:

Ø Illumination experiment: To test the fact that more working comfort would ensure better performance. The lights that illuminated the factory were reduced in numbers.

Ø Relay assembly test room experiment: Changes in Supervision, Job rotation, More interaction, Flexible working hours, More wages

Ø Mass interviewing programme: Attitude towards their job, working conditions and supervision conditions

Ø Bank wiring experiments : Study on informal groups and its effectiveness in Internal

Target setting

18. Top level management:

Ø Corporate planning for the entire operations

Ø Critical, Important and Macro decisions

Ø Corporate Objectives & Goals

Ø Decide on structure of Organization, creating various positions

Ø Review , change decisions and control of all financial and operating results

19. Middle level management:

Ø Department plan, Goals, activities

Ø Means of achieving the goals

Ø To perform all managerial functions

Ø Issue detailed orders and instructions

Ø Interpret policy to sub ordinates and lower level employees.

20. Lower level management

Planning of day to day work

Orders & Instructions were issued, received & Implemented

Supervising & Guiding of employees

Discipline & Team work

Performance & Improvement

21. Sole trading

Business unit which is owned and controlled by a single individual is known as a sole trading concern.

Advantages of sole trading

1. It is easy to form and close the business

2. It is easy for decision making

22. Partnership

A partnership is an association of two or more person to carry on business and to share its profits and losses.

Advantages of partnership

1. Easy to formation

2. Registration is not compulsory

23. Inter personal roles

Ø The figurehead role ( Ceremonial head)

Ø The leader role (Lead the organization towards the objective)

Ø The Liaison ( Communicating on behalf of organization to outsiders)

24. Informational roles

Ø Recipient role (Receives information)

Ø The disseminator role ( Pass on communication to subordinates)

Ø The spokes person role ( Pass on information to public & Stake holders)

25. Decision Roles

Ø The entrepreneurial role ( Invest, Direct & venture in to business)

Ø The disturbance handler role ( Crisis management)

Ø The resource allocator role ( Planning & Budgeting of resources)

Ø The negotiator role (Bargaining & offering)

26. Effectiveness: Achievement of objectives

27. Efficiency: Achievements of ends/Goals with least amount of resources.

28. Planning:

*Determination of objectives

*Forecasting and choice of course of action

*Formulation of policies, Programmes, Budgets, Schedules etc to achieve objectives

*Laying down of procedures and standard of performance

29. Organizing:

* Deciding on various activities required to achieve a goal

* Grouping and arranging the activities

* Assigning duties of all individuals working

* Assigning authority to the various designations

* Fixing up responsibility and performance standards

* Establishing horizontal and Vertical relationship

Ø 30.Staffing

* Deciding on quality and Quantity of manpower requirement and ensuring their availability with readiness to perform

à Manpower planning

à Recruitment

à Selection

à Training & Development

à Compensation

à Maintenance of human resource

31. Directing

Communication with all levels in the management Motivation: Provide means for better involvement in the task Leadership: Means to get things done

32. Controlling

All activities are performed according to standards pre decided

Taking steps in order of deviations

Handling issues and problems

33. Planning


Unit 2

"The plan is the action that orient towards goal or objective through the line of action to be followed, the stages to go through and the methods to use. Deciding on Coordinated activities that could bring in achievement of desired results.

*Planning is the future course of action towards attains the goal.

34. Objectives or Goals: Ends towards which activities are aimed or focused.

35. Strategies: Integrated Programme to achieve comprehensive objectives

36. Policies (Majors & Minors) Specific Area, Framework and Important guidelines for carrying out various activities.

37. Procedures: A required method of handling future activities. activity oriented

38. Rules: Specific required actions or Non actions that could join to form procedures, Task oriented

39. Programs: Set of clear instructions in a logical sequence to perform a particular task.

40. Budgets: Statement of expected results expressed in numbers.

41. Long range planning: Long range planning sets Long term goals and formulate specific plan to achieve it.

42. Short range planning: Determination of short term activities to achieve short term goals, thereby enabling reaching of Long term Goals through successful implementation of other short term plans also.

43. Functional planning: Planned for functional areas like Production, Marketing, Finance, R & D, Systems and HRM.

44. Objectives and goals may be defined as a 'Future destination or desired state of affairs which the organization wants to attain'

* Future direction towards organizational objectives

M C Farland: "Objectives are the goals, aims or purposes that organizations wish to achieve over varying periods of time'

Features of objectives:

(1) Basic plans : Objectives are the basis of all other plans

(2) Multiple in nature: In various functional areas and combine to bring success

(3) Arranged in hierarchy: Higher to lower level at various departments and divisions

(4) Objectives vary in time span : Long term & short span

(5) Objectives may be general or specific

· Maintenance * Operational * Productive * General

45. Concepts in MBO (Management by objectives)

Peter F Druker in 1954

Self control and Self direction

Performance appraisal – Central focus of MBO

Self appraisal and self development

The active involvement of subordinates in the appraisal process leads to commitment and creates an environment for motivation.

46. Process of MBO

Ø Setting preliminary objectives

Ø Fixing key result areas

Ø Setting subordinate's objectives

Ø Recycling objective

Ø Matching resources with objectives

Ø Periodic performance review

Ø Appraisal.

47. MBO Benefits

Ø Improvement of managing : Involvement and Motivated

Ø Clarification of organization: No misunderstanding

Ø Encouragement of personal commitment: Opportunity to contribute their ideas

Ø Development of effective controls: Verifiable Goals.

48. Strategies

"It is a complex plan for bringing organization from a given posture to a desired position in a future period of time".

49. Characteristics of strategy:

Ø Comprehensive and integrated action plan drawn for achieving objectives

Ø Strategy is based on situational analysis of organization and environmental analysis

(SWOT).

Ø Maximizing the performance and output with limited and minimum resources.

Ø Flexible enough to make changes and exploit new opportunities

Ø Flexible and dynamic in nature

Ø Long period of time plans with short term operational plans also

Ø Imposed externally by political, social, Legal and economical forces.

Ø It is interpretative planning formulated to interpret the meaning of the policies.

50. Policies:

Formulation, communication and implementation of policies.

"A policy is a general standing plan guiding the management in the conduct of enterprise management operations"

51. Characteristics of policies:

Ø Formulated in the context of objectives and seeks to contribute to the organizational objectives.

Ø Communicated to all managers.

Ø Broad guideline to the thinking and action

Ø Expression of top management to facilitate managerial decisions.

Ø Restrictive and permissive in nature.

52. Importance of policies:

Ø Speed up decision making

Ø Better delegation and decentralization of authority

Ø Coordination: Creates unity of efforts and uniformity of action and it focuses attention on organizational objectives.

Ø Simplifies control: Helps to prevent unwarranted deviations from planned course of action.

Ø Accomplishment of objectives

53. Planning premises

Planning premises are the anticipated environment in which plans are expected to operate.

Classification of planning premises

1. Internal and external premises

2. Tangible and intangible premises

3. Controllable and uncontrollable premises.

54. Decision making

"Selection of a course of action from or among alternatives" Choosing from available alternatives

55. Components of decision making process

Ø Decision maker

Ø Decision problem

Ø Environment around the problem

Ø Objectives of decision maker

Ø Alternative course of action

Ø Outcomes expected from various alternatives

Ø Final choice

56. Routine and strategic decisions

Routine: Regular, Normal, day to day, less significance, No deviations

Strategic: Critical, high value, responsible for success/failure of the organization.

57. Policy and operating decisions

Policy: Vital importance and taken by top management

Operating decisions: Lower levels of management, activities, tasks and processes.

58.Organizational and Personal decision

Organizational: Official capacity

Personal decisions: Individual

59. Programmed and non programmed decisions:

Programmed: Routine and Repetitive

Non programmed decisions : Situational, Accidental and Contingency

60. Individual and Group decisions Individual: Decisions of own by Leaders Group: Collective decisions

Ø Quantitative techniques:

1. Time series analysis ; Adjusted to trend, seasonal variations

2. Extrapolation: Future projection based on past & Present trends

3. Regression analysis : Relative movements of one more interrelated series.

4. Input – output analysis : Cause- effect estimation

5. Econometric model: Expressing in quantitative terms the relationship between different variables that could influence.

61. Organization:


Unit 3

"Different things ( Roles and responsibilities) to different people ( Individuals in the organization)".

Ø Formalized intentional structure of roles and positions.

62. Organizing means

Ø Identification and classification of required activities.

Ø Grouping of activities necessary to attain objectives.

Ø Assignment and delegation of authority to implement it

Ø Horizontal and vertical coordination and control. Organizational structure: designed to

Clarifies who is to do what tasks and who is responsible for what results. To remove obstacles to performance.

To make decisions and communicating it to all levels of management.

63. Formal and Informal organization:

Formal organization: the intentional structure of roles in a formally organized enterprise- A structure in which each individuals would deliver duties and responsibilities. Not a voluntary structure for employees.

Informal organization: A network of personal and social relations not established or required by the formal organization but arising spontaneously as people associate with one another".

Grape vine: An informal way of communication taking place inside the organization through rumors.

64. Process of organizing involves:

Ø Determining activities, Grouping activities, Assigning duties

Ø Delegating authority and Coordinating activities

65. Line organization: Scalar organization

Ø Direct lines of authority flowing from top to bottom levels of organization.

Ø Features:

Ø Scalar chain from top to bottom

Ø No provision for staff experts

Ø Orders flow directly from superiors to subordinate

Ø Subordinate responsible for achieving work to the superior.

Ø Each superior is independent and takes decisions in his own area

Ø Each individual responsible for executive only

Ø Direct vertical flow of authority

Ø Authority-Highest at the top and reduces towards lower level.

Ø Planning and doing by same person

66. Functional organization

Organization in which various activities are classified in to a number of functions such as production, Marketing, Finance, Personnel, etc and each function is placed under the charge of functional expert.

Features:

Entire work of organization is divided in to major functions. Every function is under the charge of a specialist

Every functional expert is given functional authority to command people of other departments concerning his function.

Every subordinate receives instructions from a group of specialist.

67. Line and staff organization

"Designed to maintain a proper balance between centralization (Line organization) and divisions of control (Functional organization).

Features:

Ø Line authority are used

Ø Direct chain of command

Ø Staff experts play a supportive role

Ø Specialized activities and basic activities are separated

Ø Unity of command is maintained.

67. Matrix Organization:

Hybrid structure combining functional departmentation and project structure.

Functional structure is a permanent feature of the matrix organization and retains authority for the overall operation of functional units. Project departments and project teams are created when ever specific projects require a high degree of technical skill and other resources for a temporary period.

Developed to meet the needs of large and complex organizations which require a structure more flexible and technically oriented rather than the functional structures.

Advantages:

Ø Helps focused attention , talent, resource usage – Better control

Ø More flexible-Effective communication

Ø Professionals can test their competence and make maximum contributions.

Ø Motivate the staff to work for completion of project- Priority

Ø Physical resources are assigned, Better balance and job security.

68. Departmentation

Grouping of similar activities of the business into departmentation, division units.

Departmentation by different strategies

1. Department by numbers

2. Department by time

3. Department by enterprise function

4. Department by Territory

5. Department by Customers

6. Department by process

7. Department by product or service.

69. Delegation of authority

Ø The process by which a manager shares some of his functions and authority with subordinates is called delegation of authority.

Ø Delegation involves assigning duties, entrusting authority and imposing responsibility on subordinates.

Ø Delegation is always done within certain limit.

Ø After delegation , the manager should have the responsibility to follow it up.

Ø Delegated authority could be taken back at the time by higher official.

Ø Supervisor exercises control over operations of authority

Ø Routine works are delegated and the manager con focus on other important matters.

Ø Delegation of authority based on division of work

Ø Systematic process.

70. Process of delegation:

Ø Assignment of duties: Defines the tasks to be performed by the subordinates.

Ø Granting of authority: Providing authority to perform tasks or activities.

Ø Creating of responsibility: Subordinates become accountable for the performance of their duties..

71. Authority: Implies right and power of a person to exercise discretion to make decisions, to issue orders, to use organizational resources and to hire and fire employees.

Hendry fayol on Authority " The right to give order and the power to exact obedience".

72. Responsibility: Obligation to perform the given task to the best of one's abilities.

73. Centralization: Centralization of authority refers to systematic and consistent retention or concentration of authority for decision making at higher levels of management.

74. Decentralization: Systematic dispersal of authority in all departments and at all levels of management. An organization said to be decentralized when managers at middle and lower levels are given the authority to take decisions on matters referring to their functions.

75. Staffing

Staffing basically involves matching jobs and individuals

76. Role of staffing

1. Increase in the number of employees

2. Changing employee roles and values

3.Increasing the percentage of woman employees

4. Widening the functions of the management

5. Effective attainment of organization goals

6. Provision of job satisfaction to employees.

77. Factors affecting staffing

1. Political factors

2. Economic factors

3. Social factors

4. Legal factors

5. Customers

6. Technological factors

78. Job specification: Formal statement of the minimum acceptable human qualities required for the successful performance of a job.

o Qualification required

Educational qualification

Experience

Training

Physical standards Communication abilities Degree of initiative

Judgment & Decision making

Human attributes (i.e) Behavioral an emotional aspects

Manager (Finance) Identification: MG (F) 31/2002

Designation: Manager ( Finance)

Age limit : 40 to 50 ( Relaxable by 5 years in exceptional cases) Educational qualification: CA/ ICWA

Degree or Diploma in financial management

Desirable: MBA or Mcom. From any recognized university. Experience: Relevant Industry : Minimum 3 years

Other Industry : Minimum 5 years

Physique: Height, Weight, General health and ailment

Special skills : Ability to work in computerized environment

Position in Organization: Middle level management to report to direct ( Finance).

79.Recruitment:Process of searching for prospective employees and stimulating them (motivate them) to apply for jobs in the organization.

80.Sources of Recruitment

Promotion, Training & Personal contact, Placement services,

Development & Transfer Advertisement, On campus recruitment, Educational Institution, Factory gate appointment, Labour contractors

81. Directing


Unit 4

Directing is a managerial function which primarily concerned with influencing, guiding, supervising and inspiring subordinates in a planned manner.

" All those activities which are designed to encourage subordinates to work efficiently and effectively in both the short and long run".

82. Process of directing involves

Ø Orders about work to subordinates

Ø Guiding, Counseling, and educating subordinates

Ø Supervising the work being performed

Ø Maintaining discipline and rewarding efficient workers

Ø Motivating and inspiring the subordinates

83. Nature of directing

Ø Directing is a sub function between organizing, Staffing and Controlling

Ø It is an initiating function. Giving orders and instructions for converting decisions in to actions.

Ø Continuous process

Ø Performed by all managers at every level of organization.

Ø The time for directing will increase when we move down the level in organization

Ø Action oriented items converting objectives in to achievement of objectives.

Ø It connects planning, Organizing, staffing and Controlling

Ø Issuing orders, Instructions and activity to subordinates.

84. Motivation:

S R S Performance = Ability X Motivation X Technology

Motive : An inner state that activates energizes or moves an individual and channelizes his behavior towards goals.

Motivation is a process of stimulating people to action in order to accomplish desired goals.

85. Importance of motivation:

Ø Effective use of resources

Ø Higher efficiency

Ø Accomplishment of organizational goals

Ø Reduced labor turnover and absenteeism

Ø Healthy Industrial relation

Ø Improved corporate image

86. Maslow's Hierarchy Need hierarchy theory

Ø Hierarchical placement of human needs from lower to higher order

If a given level of needs are satisfied fully, by providing these needs will not motivate him. He goes to next higher level of needs.

87. Herzberg's motivation Hygiene theory (Two factor theory)

But unlike Maslow's theory that the movement to next level shall happen when lower level is achieved is not practical because there is overlapping of needs

Dissatisfiers (Hygiene factors) Satisfactors (Motivational factors) Dissatifiers: Satisfactors:

Policy, administration, Supervision, Achievement, Recognition, Challenging

Working conditions, Interpersonal relations, work, advancement

Salary, Status, Job security, personal life

Needs

Hygiene factors are the needs that would not be felt as a motivator when it is present, but when it is absent the dissatisfaction is felt (Maintenance factors). i.e. Electricity & Salary

The motivational factors are the needs that would motivate an employee to perform.

Herzberg was able to recommend the importance of satisfiers which can motivate the employees.

88. Expectancy theory of motivation: Victor H Vroom

"People will be motivated to do things to reach goal if they believe in the worth of that goal and if they can see that what they do will help them in achieving it".

Force = Valence & Expectancy

Valance: Strength of an individual's preference for an outcome

Expectancy: Probability that a particular action will lead to a desired outcome.

89. Porter and Lawler model

Amount of effort à depends on Value of reward + Amount of effort + Probability of actually getting a reward

90. Equity theory by J.Stacy Adams

Outcomes by a person = Outcomes by another person/ Inputs by another person

Individual's subjective judgements about the fairness of the reward she or he got, relative to the inputs (which include many factors such as effort, experience and education) in comparison with the rewards of other.

91. Reinforcement theory : BK. Skinner

Positive reinforcement or behaviour modification.

"Individuals can be motivated by proper design of their work environment and praise for their performance and that punishment for poor performance produces negative results.

MC Gregor's participation theory

(Theory X and Theory Y)

Theory X (Traditional theory) Negative assumptions about human behavior

(1) People are by nature indolent ( want to work as little as possible)

(2) People lack ambition, dislike responsibility and prefer to be directed by others.

(3) People are inherently self centered and indifferent to organizational needs and goals. (4) People are generally gullible (not sharp and bright).

This approach leads to

Close supervision, centralized structure, autocratic leadership and tight controls.

Management is responsible for organizing the elements of production Management involves directing their efforts, motivating and controlling them. Active intervention needed for accomplishing results.

Theory Y

(1) People are not by nature passive or resistant to organizational goals. (2) The want to assume responsibility.

(3) They want their organization to succeed.

(4) People are capable of directing their own behavior. (5) They have need for achievement

This approach leads to

Ø Democratic leadership.

Ø Participation in decision making

Ø Self control

Ø Management by objectives

Ø Job enrichment

Ø Decentralization

Ø Employees are treated as naturally responsible and self motivated.

92.Mc clelland's Needs theory of motivation:

Three basic motivating needs n/Pwr à Need for power

n/ Aff à Need for affiliation

n/ Ach à Need for achievement

Need for power : People with high need for power have a great concern for exercising influence and control –Forceful, outspoken, hard headed and demanding.

Need for affiliation: Usually derive pleasure from being loved and tend to avoid the pain of being rejected.

Need for achievement: Need for achievement have an intense desire for success and an equally intense fear of failure – risk taking, energetic and hardworking.

93. Leadership:

Ø Influence, art or process of enabling people to strive willingly and enthusiastically towards the achievement of group goals.

Ø Ability to persuade others to seek defined objectives enthusiastically. It is the human factor which binds a group together and motivates it towards goals.

94. Nature and Features

Ø Leadership is basically a personal quality

Ø Ability to form a group and enable them to follow his instructions without hesitation.

Ø Leadership pre supposes (assumes) a group of followers, who will follow

Ø Leadership is a process of inert- personal influence by which leader influences the followers in a situation to strive willingly towards realization of common goals.

Ø Community of interests between the leader and his followers.

Ø Continues process of influencing behavior.

Ø Leadership is exercised in a particular situation at a given point of time and under a specific set of circumstances.

Ø Leadership is a reciprocal relationship.

95. Leadership skills

1. Visionary skills 2. Communication skills 3. Sensitivity skills 4. Self awareness skills

96. Qualities of a good leader

1. intelligence 2. Physical features 3. Maturity 4. Vision and foresight 5.Inner motivation 6. Sense of responsibility 7. Empathy 8. Human relations attitude 9. Emotional balance

97. Autocratic or authoritarian leadership:

Leader centralizes power and decision making in himself. Commands complete control over subordinates.

Ø Strict autocrat leader: Penalties criticism and coercion

Ø Blue violent autocrat leader : Centralizes decision making power in him and offer positive motivation style in the room of taking in to account the feelings and needs of subordinates

Ø In competent autocrat leader : He adopts an autocratic style just to hide his incompetence.

Advantages:

Ø Provides strong motivation and reward to the self centered leader

Ø Permits quick decisions

Ø Incompetent subordinates can work, as their role in decision making is negligible

98. Democratic or Participative style:

Leaders take decision in consultation with the subordinates. Advantages:

Ø Provides subordinates to develop their potential abilities and greater responsibilities

Ø Improves job satisfaction & Morale of subordinates

Ø Subordinates participation would improve the quality of decisions.

99. Laiseez – Faire ( Free Rein Leadership)

Allows group to establish its own goals and work out its own problems. The entire decision making power is entrusted to subordinates and leader do not direct them.

Advantages:

Higher involvement and responsibility

Career development is successful

100. Creativity

Ability to produce new and useful ideas through the combination of known principles and components in novel and non obvious ways.

101. Creative process

1. Saturation

2. Preparation

3. Frustration and incubation

4. Inspiration

5. Verification


Unit 5

Controlling

102. Elements of control system –Stanley De J. Osberne

Ø Planning: Plan is a pre requisite for effective control

Ø Organizational structure: Clearly defining the duties and responsibilities of each individual.

Ø Proper operating policy: Policy in realistic and broad in scope based on calculated action.

Ø Delegation or decentralization of authority: People down the line must be given right to make normal decision and normal errors to accomplish the objectives set before.

Ø Up to date procedures: Maintenance of up to date procedures and ensuring that these procedures are followed.

Ø Communication: Appraisal of results and guide for forward planning

Ø Personal ability of the controller:

Ø Proper assignment of authority and responsibility

103.8 areas of control – Peter F Drukker

-Marketing, Innovation, Productivity, Human organization, financial resources, Physical resources, Profitability and Social responsibility.

104. Holden's 13 areas of control

Policies, Organization, Personnel, wages and salaries, Cost, Methods and manpower, Capital expenditure, service dept. efforts, Line of products, Research & Development, foreign operations, External relations and over all control.

105. Functional budget: One that relates to a function of the business i.e. Sales, Promotion etc.

106.Master budget: It is the summary budget incorporating its component functional budgets consolidated department and functional budget.

107.Fixed budget: Budget designed to remain unchanged irrespective of the level of activity actually attained.

108.Flexible budget: Designed to adjust permitted cost levels to suit the level of activity actually attained.

109.Zero based budget: (ZBB) Each manager has to justify the resources for each activity afresh for the accomplishment of objectives.

110.CPM : Critical path method : It is similar to PERT in attempt to integrate all activities involved in a project.

111.The differences between PERT and CPM are

Ø CPM assumes that the duration of each activity is constant. PERT allows uncertainty in the duration of activities.

Ø PERT is event oriented, CPM is activity oriented.

Ø CPM assumes some previous work experience essential for the completion of each activity. For PERT previous work experience is not essential.

Ø Cost and time estimates are used in CPM, but only time estimate is used in PERT.

112.Network techniques:

PERT : Program evaluation and review techniques.

PERT is a time event network analysis system in which various event in a program or project are identified, with a planned time established for each. These events are placed in a network showing the relationship of each event to the others.

à Events

Circles are number in an order of occurrence

Arrow represents an activity

Three time estimates are used

1. Most likely time

2. Optimistic time

3. Pessimistic time

Critical path : The sequence of events which takes the longest time and which has Zero ( or the least) slack time.

Strengths :

Ø Forces the manager to plan

Ø Planning is done all the way down the line

Ø Concentrates attention on critical elements that may need correction

Ø Makes possible a kind of forward looking control

Ø Network systems with sub systems enables a manager to aim reports and pressure for action at the right spot.

113.Quality control: Group of voluntary representation from each departments, who are working on continuous improvement of performance.

114.productivity

It is a measure of how much input is required to produce a given input. productivity=output/ input

114.Globalisation:

The government attitude towards the business has undergone a drastic change beginning from the later years of eighties. This change can be seen from the various policies announced by the government particularly.

Ø Industrial policy statement

Ø Long term fiscal policy

Ø Exim policy

115. Liberalisation:

It eliminates licensing quantitative restrictions and other regulatory and discretionary controls.

The liberalization has enormously expanded the scope of the private sector. Now only a small number a industries are reserved. The liberalization of the policies towards foreign capital and technology and import liberalization have given further growth and competition.

LPG- LIBERALISATION PRIVATISATION GLOBALISATION

PROPULSION-I Questions Bank 2014



PROPULSION-I Questions Bank 2014

Anna University, Chennai

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16 MARKS QUESTION UNIT - I

1. An advanced fighter engine operating at Mach 0.8 and 10Km altitude where, Ta=223.297K & Pa=0.2649 bar has the following uninstalled performance data and uses a fuel with C.V=

42,800KJ/Kg:

Thrust = 50 KN Mass flow of air = 45Kg/s Mass flow of fuel = 2.65 Kg/s

Determine the specific thrust, thrust specific fuel consumption; exit velocity, thermal efficiency, propulsion efficiency, and overall efficiency (assume exit pressure equal to ambient pressure). 16

2. Find specific thrust and SFC of a simple turbojet engine, having the following component performance at which the cruise speed and altitude are M 0.8 and 10000m. Select ambient condition from the gas table.

Compressor pressure ratio Turbine inlet temperature Isentropic efficiency:

8.0

1200K

Of compressor ηc

0.87

Of turbine ηt

0.90

Of intake ηi

0.93

Of propelling nozzle ηj

0.95

Mechanical transmission efficiency ηm

0.99

Combustion efficiency ηb

Combustion chamber pressure loss ∆Pb

0.98

4% of compressor outlet pressure.

C.V of fuel is 43,000 KJ/Kg, assume data if necessary, Cpa ≠ Cpg 16

3. (a) Explain with neat sketch operating principles of turbofan engine 8 (b) What is thrust augmentation? Explain any two methods of thrust augmentation with

sketches. 8

4. Compare the characteristics, advantages & disadvantages of turbojet, turbofan and turboprop engine.

5. (i)Discuss the different methods of thrust augmentation. Draw T-S diagram for turbojet engine with thrust augmentation. 8

(ii) Discuss the typical turbojet cycle performance with suitable sketches. 8

6. A turbojet engine is traveling at 270 m/s at an altitude of 5000m. The compressor pressure ratio is 8:1 and maximum cycle temperature is 1200K. By assuming the following data,

Ram efficiency 93% Isentropic efficiency of compressor 87%

Pressure loss in combustion chamber 4%of compressor delivery pressure

Calorific value of fuel 43,100 kj/kg Combustion efficiency 98% Mechanical transmission efficiency 99% Isentropic efficiency of turbine 90% Propelling nozzle efficiency 95% Ambient conditions at 5000 m are 0.5405 bar and 255.7 K.

Calculate the

(i) Specific thrust and

(ii) TSFC 16

7. (i) Define thrust of an engine and derive the thrust equation for a general propulsion system. 8

(ii) Discuss the typical turbojet cycle performance with suitable sketches. 8

8. An ideal turbojet flies at sea level at a Mach number of 0.75. It ingests 74.83 kg/s of air, and the compressor operates with a total pressure ratio of 15. The fuel has a heating value of 41,000 kj/kg, and the burner exit total temperature is 1389 K. Find the thrust developed and the TSFC. Assume that the specific heat ratio is 1.4. 16

9. Air enters a turbojet engine at a rate of 12*104 kg/h at 150C &1.03 bar and is compressed adiabatically to 1820C & four times the pressure. Products of combustion enter the turbine at

8150C & leave it at 6500C to enter the nozzle. Calculate the isentropic efficiency of the compressor, the power required to drive the compressor, the exit speed of gasses & thrust developed when flying at 800 km/h. Assume the isentropic efficiency of the turbine is same as that of the compressor and the nozzle efficiency is 90%.Assume the data required suitably. 16

10. A jet propelled plane consuming air at the rate of 18.2 kg/s is to fly at Mach number of 0.6 at an altitude of 4500m (Pa = 0.55 bar, Ta = 255K ). The diffuser which has a pressure coefficient of 0.9, decreases the flow to a negligible velocity. The compressor pressure ratio is 5 & maximum temperature in the combustion chamber is 1273 K. After expanding in the turbine, the gases continue to expand in the nozzle to a pressure of 0.69 bar. The isentropic efficiency of compressor, turbine and nozzle are 0.81, 0.85 & 0.915 respectively. The heating value of the fuel is 45870 kj/kg. Assume Cp = 1.005 kj/kg-K, Cpg = 1.147 kj/kg-K. Calculate

(i) Power input to the compressor

(ii) Power output of the turbine

(iii) The fuel air ratio

(iv) The thrust provided by the engine

(v) The thrust power developed. 16

1. (i) Explain successive steps in the acceleration and over speeding of a one- dimensional supersonic inlet with sketches. 8

(ii) Derive the relation between area ratio Amax/Ai and external deceleration ratio ui/ua. 8

2. A supersonic inlet is designed with a two-dimensional conical spike (with two half-cone angles 100 and 200 relative to the axial centerline, respectively). The inlet is to operate at a flight Mach number of 1.9.The two standing oblique shocks are attached to the spike and cowl, and a converging inlet section with a throat of area A* is used to decelerate the flow through internal compression. Assume γ = 1.4 and internal diffuser pressure recover factor Πr = 0.97. Estimate the overall recovery factor Πd on the assumption that the inlet starts (i.e., the normal shock is swallowed). Also, find the required A*/A1.

3. What are the different modes of inlet operation? Explain with suitable sketches. 16

4. Air enters a two-dimensional supersonic diffuser at a pressure of 14.102 kPa, a temperature of

217 K, and with a Mach number of 3.0. The two-dimensional oblique shock diffuser has an oblique shock angle of 27.80, which is followed by a normal shock. Determine, assuming constant specific heats.

(i) The velocity, total temperature and pressure of the air entering the oblique shock. (ii) The Mach number, total pressure after the oblique shock.

(iii) The flow deflection angle.

(iv) The Mach number, total and static pressure and static temperature after the normal shock.


UNIT-III

1. (a) What are the important factors affecting combustor design? 8 (b)Write down the methods of flame stabilization and explain with sketch. 8

2. (a)What are the three types of combustion chamber? Compare its advantages and disadvantages. 8

(b) Name the material used for combustion chamber and discuss the special qualities of the material used for combustion chamber? 8

3. (a)What are the factors affecting combustion chamber? Explain briefly? 8

(b) With the aid of a simplified picture explain the operation of a flame holder. 8

4. (i) With a neat sketch explain the working of a combustion chamber. 8

(ii) Consider n-decane fuel, balance the chemical equation for the stoichiometric combustion of this fuel in air and find the stoichiometric fuel-to-air ratio. 8


UNIT-IV

1. (a) Plot Mach number, static temperature, static pressure and static density variations along the longitudinal axis of a convergent-divergent nozzle, when it flows full. Explain the variations. 8

(b)A De Laval nozzle has to be designed for an exit Mach number of 1.5 with exit diameter of

200 mm. Find the ratio of throat area/exit area necessary. The reservoir conditions are given as Po = 106 Pa, To = 200C. Find also the maximum mass flow rate through the nozzle. What will be the exit pressure and temperature? 8

2. A converging-diverging is designed to operate with an exit Mach number of 1.75. The nozzle is supplied from an air reservoir at 68bar (abs.). Assuming 1-d flow, calculate:

(i) Maximum backpressure to choke the nozzle. 4 (ii) Range of backpressure over which a normal shock will appear in the nozzle. 4 (iii) Back pressure for the nozzle to be perfectly expanded to design M. 4 (iv) Range of back pressure for supersonic flow at the nozzle exit plane. 4

3. (i) What are the types of nozzle? Explain various operating conditions of a C-D nozzle with suitable sketch. 8

(ii) Write short notes on the following:

(a) Ejector and variable area nozzles 4 (b) Thrust reversing 4

1. An axial compressor stage has a mean diameter of 60cm and runs at 15000rpm. If the actual temperature rise and pressure ratio developed are 300C and 1.4 respectively.

(i) The power required to drive the compressor while delivering 57 Kg/s of air; assume mechanical efficiency of 86 % and an initial temperature of 350C.

(ii) The stage loading coefficient. (iii) The stage efficiency and

(iv) The degree of reaction if the temperature at the rotor exits is 550C.

2. (i) Explain the working of a centrifugal compressor and draw the velocity

triangles. 8

(ii) A centrifugal compressor has an impeller tip speed of 366 m/s. Determine the absolute Mach number of the flow leaving the radial vanes of the impeller when the radial component of velocity at impeller exit is 30.5 m/s and the slip factor is 0.9. Given that the flow area at impeller exit is 0.1m2 and the total-to-total efficiency of the impeller is 90%, determine the mass flow rate. 8

3. (i) A sixteen-stage axial flow compressor is to have a pressure ratio of 6.3. Tests have shown that a stage total-to-total efficiency of 0.9 can be obtained for each of the first six stages and 0.89 for each of the remaining ten stages. Assuming constant work done in each stage and similar stages fine the compressor overall total-to –total efficiency. For a mass flow rate of 40 kg/s determine the power required by the compressor. Assume an inlet total temperature of 288

K. 8

(ii) Discuss the factors affecting stage pressure rise of an axial flow compressor with suitable sketches. 8

4. A stage of a radial compressor is to be analyzed. It rotates at 12,300 rpm and compresses

31.75 kg/s of air. The inlet pressure and temperature are 241.325 kPa and 306K respectively. The hub and tip radii of the blades at the inlet are 7.62 and 13.97cm respectively. The exit radius is

27.94cm and the exit blade height is 2.54cm. The slip factor is unity. Flow enters the inducer with no prewhirl and the impeller has straight radial blades. The efficiency of the stage is 88%. The value of Cp and γ are 1.005 kj/kg-K and 1.397 respectively.

Find the following:

(i) Mean relative flow angle at the inlet.

(ii) The static pressure at the impeller exit. (iii) The total pressure ratio for the stage,

(iv) The Mach numbers at the impeller inlet and exit.

(v) The required power for the stage. 16

5. An axial flow compressor stage is designed to give free-vortex tangential velocity distributions for all radii before and after the rotor blade row. The tip diameter is constant and 1.0m; the hub

diameter is 0.9m and constant for the stage. at the rotor tip the flow angles are as follows: 16

Absolute inlet angle, α1 = 300

Relative inlet angle, β1 = 600

Absolute outlet angle, α2 = 600

Relative outlet angle, β2 = 300

.Determine,

(i) the axial velocity

(ii) the mass flow rate

(iii) the power absorbed by the stage

(iv) the flow angles at the hub

(v) the reaction ratio of the state at the hub

Given that the rotational speed of the rotor is 6000 rpm and the gas density is 1.5 kg/m3 which can be assumed constant for the stage. It can be further assumed that stagnation enthalpy and entropy are constant and after the rotor row.

6. The mass flow rate of flow at 288 K and 101.3 KPa at the inlet to the impeller of the centrifugal-flow compressor is 1.814 kg/s. The inlet flow is in the axial direction. The impeller eye has the minimum diameter of 3.81cm and a maximum diameter of 12.7cm and rotates at

35,000rpm. Assuming no blockage due to the blade, calculate the ideal angle at the hub and tip at the inlet to the impeller. Draw velocity diagram at the hub and at the tip

PROPULSION-I Two Marks Questions With Answers 2014



PROPULSION-I Two Marks Questions With Answers 2014

2 MARKS QUESTION WITH ANSWERS

UNIT-1

1. Define Froude efficiency, what is its effect on thrust?

From the propulsion power and the thrust power, we can derive the propulsive

efficiency _prop, also known as the Froude efficiency. It is given by

Propulsive efficiency = Pthrust/Pprop

2. Compare air breathing engine and rocket engine.

air breathing engine are combustion engines that use the oxygen in atmospheric air to oxidize ('burn') the fuel carried, rather than carrying an oxidizer, as in a rocket. Theoretically, this should result in a better specific impulse than for rocket engines.

A continuous stream of air flows through the Air-breathing engine. This air is compressed, mixed with fuel, ignited and expelled as the exhaust gas. Thrust produced by a typical air- breathing engine is about eight times greater than its weight. The maximum velocity of Air- breathing engines is limited to 1-3 km/s due to extreme temperature and dissociation of the exhaust gas; however, the maximum velocity of a hydrogen-breathing engine of the same design is about 4 times higher.

3. Define SFC.Write down its significance.

SFC, is an engineering term that is used to describe the fuelefficiency of an engine design

with respect to thrust output. It allows the efficiency of different sized engines to be directly compared.

SFC is dependent on engine design, but differences in the SFC between different engines using the same underlying technology tend to be quite small. Increasing overall pressure ratio on jet engines tends to decrease SFC.

4. What are the factors affecting thrust?

The Jet engine is much more sensitive to operating variables . Those are:

1.) Engine rpm.

2.) Size of nozzle area.

3.) Weight of fuel flow.

4.) Amount of air bled from the compressor

6. Define by pass ratio.

It is defined as the ratio between the mass flow rate of air drawn through a fan disk which

bypasses the engine core (un-combusted air), to the mass flow rate passing through the engine core which is involved in combustion to produce mechanical energy

8. Differentiate between Scramjet & Ramjet engine.

In a ramjet, the combustion chamber - where the air is mixed with fuel and ignited - only works

at subsonic speeds. So the intake slows the air down, releasing some of its energy as a shock wave, but this reduces fuel efficiency. The scramjet is an innovation on the ramjet in which the combustion chamber is specially designed to operate with supersonic airflow. Scramjet is simply an acronym for 'supersonic combustion' ramjet.

10. What are the advantages and disadvantages of cooling gas turbine blades?

There are three main types of cooling used in gas turbine blades; convection, film, and

transpiration cooling. While all three methods have their differences, they all work by using cooler air (often bleed from the compressor) to remove heat from the turbine blades.

11. Mention relative merits of jet engines over piston engines.

• Simple design with few moving parts, giving a compact engine with low maintenance costs and reduced frictional losses.

• The operational flexibility through the variable compression ratio allows operation optimisation for all operating conditions and multi-fuel operation. The free-piston engine is further well suited for homogeneouschargecompressionignition (HCCI) operation


UNIT-II

1. What are the requirements of an aircraft intake?

The air intake requires enormous effort properly to control airflow to theengine.

The intake must be designed to provide the appropriate amount of airflow required by the engine

.Furthermore this flow when leaving the intake section to enter thecompressor should be uniform stable and of high quality.

Good air intake design is therefore a prerequisite if installed engineperformance is to come close to performance figures obtained at thestatic test bench

2. Write notes on pressure recovery factor of the intake?

The ratio between pressure of air intakes the engine to the pressure level of atmosphere

P01/Pa = P01/PaxP0a/Pa

3. What are the starting problems in supersonic inlets?

For air-breathing engines on supersonic vehicles,

usually want to slow flow down to subsonic speeds inside engine

– need diffuser (M>1→M<1) for engine inlet

– exception: supersonic combustion (e.g., SCRAM jets)

• Goal

– lowestpo loss (highest thrust)

• given flight M

• mass flow rate requirement (thrust)

• stable operation (nothing drastic for small changes in flight conditions)

4.What are the factors to be considered while designing a subsonic inlet?

1. High total pressure ratio

2. Good uniform of flow

3. Low installation drag

4. Good starting and stability.

5.What are the factors to be considered while designing a supersonic inlet?

1. Provide adequate subsonic performance

2. High pressure recovery factors

3. Good pressure distribution at the compressor inlet

6. What is meant by sub critical mode of inlet operation? State its advantages and disadvantages.

Some inlets are designed to operate in the subcritical mode with a margin of stable operation.

Stagnation

pressure recovery is normally equal to or less than the value for critical operation. The capture area ratio is less than one, since air is expelled from the inlet opening, with a resulting increase in drag due to the subsonic air-stream passing over the cowl lip.


UNIT-III

1. Define equivalence ratio and stochiometric fuel air ratio.

A stoichiometric amount or stoichiometric ratio of a reagent is the optimum amount or ratio

where, assuming that the reaction proceeds to completion:

1. all reagent is consumed

2. there is no shortfall of reagent

3. no residues remain.

2. Define efficiency of the combustion.

Combustion efficiency is a calculation of how well your equipment is burning a specific fuel, shown in percent. Complete combustion efficiency would extract all the energy available in the fuel. However 100% combustion efficiency is not realistically achievable. Common combustion processes produce efficiencies from 10% to 95%. Combustion efficiency calculations assume complete fuel combustion and are based on three factors:

The chemistry of the fuel.

The net temperature of the stack gases.

The percentage of oxygen or CO2 by volume after combustion.

3.What is the purpose of primary air in combustion chamber?

The purpose of the primary air is as follows,

1. 30% of the air intakes the engine used in combustion process

2. 20% of air used in compression process

3. Remaining 50% of used primary used in cooling process

4.What is the purpose of secondary air in combustion chamber?

The purpose of the secondary air is as follows,

1. Used in external turbine cooling

2. Thrust reversal operation

3. Afterburner operation

5.What is the purpose of dilution air in combustion chamber?

Dilution air is also called as tertiary air, It is used in cooling the burning

surfaces.

6.Define combustion intensity?

The ratio between heat released by the combustor and the addition of combustion volume and

pressure

7.State the advantages and disadvantages of annular combustor.

i)The burner at the left is an annular combustor with the liner sitting inside the outer casing which has been peeled open in the drawing. Many modern burners have an annular design.

ii)The burner in the middle is an older can or tubular design. The photo at the top left shows some actual burner cans. Each can has both a liner and a casing, and the cans are arranged around the central shaft.

iii)A compromise design is shown at the right. This is a can-annular design, in which the casing is annular and the liner is can-shaped. The advantage to the can-annular design is that the individual cans are more easily designed, tested, and serviced.


UNIT-IV

1. What is choked nozzle?

An expansion nozzle in which the gas velocity has reached sonic level at the

throat

2. What are the types of nozzle in gas turbine engine?

1. Convergent nozzle

2. CD nozzle

3. Give any four functions of an exhaust nozzle.

1. Allow for cooling of walls,

2. Allow for thrust reversing

3. Thrust vector should be controllable

4. Define under expanded nozzle.

An under expansion nozzle in which the gas exit pressure at the nozzle is greater than the

back pressure.

5. Define over expanded nozzle.

An over expansion nozzle in which the gas exit pressure at the nozzle is lesser than

the back pressure.

6. Define optimum expansion nozzle.

An optimum expansion nozzle in which the gas exit pressure at the nozzle is equal to

the back pressure


UNIT-V

1. Write down the difference between centrifugal and axial flow compressor.

*Axial compressors are rotating, airfoil based compressors in which the working fluid

principally flows parallel to the axis of rotation. This is in contrast with centrifugal, axi- centrifugal and mixed-flow compressors where the air may enter axially but will have a significant radial component on exit.

*Centrifugal fan/blowers are more suited to continuous-duty applications such as ventilation fans, air movers, cooling units, and other uses that require high volume with little or no pressure increase. In contrast, multi-stage reciprocating compressors often achieve discharge

pressures of 8,000 to 10,000 psi (59 MPa to 69MPa). One example of an application of centrifugal compressors is their use in re-injecting natural gas back into oil fields to increase oil production

2. Define Elementary Airfoil Theory

When a single airfoil is parallel to the velocity of a flowing gas, the air flows over the

airfoil as shown in figure 7a. The airdivides around the body, separates at the leading edge, and joins again at the trailing edge of the body. The main stream itself suffers no permanent deflection from the presence of the airfoil. Forces are applied to the foil by the local distribution of the steam and the frictionof the fluid on the surface. If the airfoil is well designed, the flow is streamlined with little or no turbulence.

3. Define laminar flow airfoils.

Just before and during World War II, much attention was given to laminar-flow airfoils.

These airfoils are designed so that the lowest pressure on the surface occurs as far back as possible. The reason for this design is that the stability of the laminar boundary layer increases when the external flow is accelerated (in the flow with a pressure drop), and the stability decreases when the flow is directed against increasing pressure. A considerable reduction in skin friction is obtained by extending the laminar region in this way, provided that the surface is sufficiently smooth.

5. Define degree of reaction of axial compressor.

The degree of reaction in an axial-flow compressor is defined as the ratio of the change of static

head in the rotor to the head generating the stage

6. Define radial equilibirium.

The flow in an axial-flow compressor is defined by the continuity, momentum, and

energy equations. A complete solution to these equations is not possible because of the complexity of the flow in an axial-flow compressor. Considerable work has been done on the effects of radial flow in an axial-flow compressor. The first simplification used considers the flow axisymmetric. This simplification implies that the flow at each radial and axial station within the blade row can be represented by an average circumferential condition. Another simplification considers the radial component of the velocity as much smaller than the axial component velocity, so it can be neglected.

7. Define Diffusion Factor

The diffusion factor should be less than 0.4 for the rotor tip and less than 0.6 for the rotor

hub and the stator. The distribution of the diffusion factor throughout the compressor is not properly defined. However, the efficiency is less in the later stages due to distortions of the radial velocity distributions in the blade rows. Experimental results indicate that even though efficiency is less in the later stages, as long as the diffusion loading limits are not exceeded, the stage efficiencies remain relatively high.

Anna University, Chennai