propulsion ii qb

8/13/2019 Propulsion II QB

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UNI T-1 AIRCRAFT GAS TURBINE

PART A

1) What is need for shrouds in axial flow turbines?2) What is blade to gas speed ratio and its significance?3)Define(a)impulse stage (b)reaction stage4) State the advantages and disadvantages of cooling a gas turbine blade?5)Distinguish Between An Impulse And A Reaction Turbine?6) What is Velocity Compounding Of Multistage Impulse Turbine?7) What are impulse stage and reaction stages?8) Write short note on method of blade cooling?9)Define degree of reaction of turbine?10) What is the difference between impulse and reaction turbine?11) What is called the blade loading coefficient?12) What is called free vortex change?13) State the advantages and disadvantages of cooling a gas turbine

blade.

14) Define (a) Impulse stage (b) reaction stage.15) Distinguish between impulse and reaction turbines.16) Sketch the Temperature-Entropy diagram for ideal and actual brayton

cycle and define compressor and turbine efficiencies.

17) What is called blade loading coefficient in turbines.18) Write down the equation for loss coefficient in terms of pressure drop

for the rotor blades.

PART B

1)An axial gas turbine has an initial stagnation pressure of 350 KPa(absolute)and a stagnation temperature of 565 degree C and a negligible Velocity.at

the mean radius0.36m assume the following conditions:

Nozzle exit flow angle 68

Nozzle absolute static pressure at exit 207KPa

Stage degree of reaction 0.2 determine the flow co efficient and stage

loading factor and the reaction at the hub radius of 310 mm at the design

PROPULSION-2


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Speed of8000 rpm. Assume free vortex condition and Cp=1.148kj/kg k and

gamma=1.33 for gas

2) what is need for matching of compressor and turbine?write down thematching procedure with suitable sketches.

3) explain the working principle of an ideal impulse turbine and elaborate itwith the velocity triangles and temperatures-entropy diagram. also write

down the application of this machine

4) derive an expression for work output by a turbine stage also deduce it fortangential component at the exit is zero.

5) derive the relation for degree of reaction in terms of pressure, velocity,enthalpy and flow geometry

6)Explain zero Percent,Fifty Percent And Hundred Percent Reaction Stage.7)Explain As To Why Turbines Always Have Greater Efficiency Than

Compressors.

8)In A single stage impulse turbine the nozzle discharge the fluid on to theblades at an Angle of 65 degrees to the axial direction and the fluid leaves

the blades with an absolute velocity of 300m/s at an angle of 30 degrees to

the axial direction.if the blades have equal inlet and outlet angles and there

is no axial thrust,estimate the blade angle,power required per kg/s of the

fluid and the blade efficiency.

9)Derive the expression for axial turbine degree of reaction with the help ofstage dynamics.

10) An axial turbine of high hub tip ratio runs with 0degree of reactionand peak efficiency at design flow and speed. The nozzle exist angel is

70(from the axial direction) estimate 1) the percentage change in torque

accompanying a 20% drop in speed (from the design value) while operating

with design mass flow. 2) Corresponding degree of reaction.

11) A singlestage gas turbine operates at its design condition with anaxial absolute flow at entry and exit from the stage. The absolute flow angle

at nozzle exit is 70 deg. At stage entry the total pressure and temperature are

311 k pa and 850 degree C respectively . The exhaust static pressure is 100

k pa, the total-to-static efficiency is 0.87 and the mean blade speed is 500

m/s.Assuming constant axial velocity through the stage, determineThe


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specific work done, The Mach number leaving the nozzle, The axial velocity,

The total-to-total efficiency, and The stage reaction

12) Show, for an axial flow turbine stage, that the relative stagnationenthalpy across the rotor does not change. Draw an enthalpy entropy

diagram for the stage labeling all salient points.

13) What is need for matching for compressor and turbine? Write downthe matching procedure with suitable sketches.

14) Define stage reaction for a turbine and derive expression for thereaction in terms of the flow angles. Draw velocity triangles for reactions of

zero, 0.5 and 1.0.

15) Why is the temperature at turbine inlet in a gas turbine enginerestricted ? Suggest a few methods of increasing this temperature without

sacrificing the life of the engine.16) Explain the different types of combustion chambers in a gas turbine

engine. Discuss their merits and demerits.

17) List out the procedure for compressorturbine matching withsuitable sketches.

18) Explain the free vortex design of turbines using the vortex theory.19) Determine the possible mean diameter for the single stage turbine

with following data:

20)

Mass flow 20 kg/s ; Isentropic efficiency 0.90; Inlet temperature1100K; Temperature drop 145K; Pressure ratio 1.873; Inlet pressure 4

bar;Rotational speed N 250 rev/s; Mean blade speed U 340 m/s; Nozzle loss

coefficient 0.05; assume suitable data if necessary.


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UNI T-2 RAMJET PROPULSION

PART-A

1) what are the applications of integral ram-rocket propulsion system?2) write down the function of isolator in scramjet engine3) how do you classify hypersonic ramjets based on combustion process?4) distinguish between ramjet and scramjet5)How is a Ramjet Different From a turbojet?6) What are the possible application of a ramjet?7)Describe ramjet engine operation principle with P-V and T-S diagram?8) Write the limitation of Scramjet engine?9) What is the advantage of ramjet when compared to other?10) What are the differences between the ramjet and scramjet engine?11) Write the basic component of ramjet?12) Write the application of ramjet?How do you classify hypersonic

ramjets based on combustion process?

13) Write down the function of isolator in a scramjet engine.14) .Explain supersonic flow cannot maintain stable combustion below

Mach 6.

15) What are different possible flow condition in supersonic nozzle?16) Draw the T-s diagram for the scramjet and compare it for ideal and

real operating cycle?

17) list 2 major disadvantages of a ram jet?18) What is the purpose of a flame holder in a ramjet?

PART B

1) with neat sketches explain critical ,sub critical ,and super critical operationof ramjet engine

2) a ramjet is to propel an aircraft at Mach no 1.5 at high altitude Whereambient pressure is 11.6 KPa and ambient temperature is 205K.the

maximum temperature in the engine is 2500 K the heating value of fuel used

is 45 MJ/Kg assume gamma=1.4 and Cp=1.0kj/kg K .if all components are


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friction less, determine (1)TSFC(2)thermal efficiency(3)propulsive

efficiency(4) over all efficiency

3) briefly discuss performance of supersonic combustion ramjet and comparesubsonic and supersonic ramjets

4) With a neat sketch explain the concept of integral ram-rocket and mentionits advantages and disadvantages

5) an ideal ramjet engine is being designed for a Mach 3.2 aircraft at analtitude of 33000 feet (222.89 k,0.26262 bar).the fuel has a heating value of

43264kj/kg, and the burner exit total temperature is 1889k.a thrust of

42.258kN is needed. what is the required air flow?what is the resulting

nozzle exit diameter?what is the resulting TSFC?

6) with the help of a temperature,Entropy diagram explain the working of aramjet engine.show on the diagram the possible losses.

7)Discuss the merits and demerits of a scramjet.8)A Ramjet travels at M=2.8 at an altitude where the pressure is 0.4 of sea-

level value and temperature is 256k. Air Flows Through The engine at 40

kg/s with a burner exit temperature of 2000k.The fuel has a heating value of

46500KJ/Kg. Estimate the fuel-air ratio,thrust and TSFC assuming a

specific heat ratio of 1.4

9)Estimate the effect of aerodynamic loss of ramjet engine.

10) A ramjet is propelled an aircraft at an Mach number 3 at high altitudewhere the ambient pressure is 8.5kpa and the ambient temperature ta is

220k, turbine inlet temperature t is 2540k. If all component of the engine are

ideal is, frictionless: determine thermal, propulsion and overall efficiency?

11) Discuss the problems associated with supersonic combustion12) Enumerate the various types of scramjet combustors and fuel injection

schemes.

13) A ramjet is to propel an aircraft at Mach 3 at an altitude where thepressure is 8.5 k pa and ambient temperature is 220 k. If the maximum

permissible temperature is 3540 k and the components are assumed to be

ideal, determine The thermal efficiency, The propulsion efficiency and the

overall efficiency.


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14) Ramjet engine has the following characteristics at the inlet computefree stream stagnation temp and efficiency for normal shock inlet . assume

data if necessary M=4 ,molecular weight=28.96443kg/kg mole r=1.4

R=287.056,Ta=216.65k Pa=19.33kpa,q=q/m=500kj/kg assume that mass of

added fuel is negligible exhaust and R are the same

15) scramjet engine has the following data :Mach at inlet is 10, altitude30 km (pressure 1.1718kpa,temp 226.65 k, ramp angle is 4 degrees Compute

the specific enthalpy of flow entering to the combustor, combustion S and the

TD efficiency of the engine .assume data if necessary and equivalence ratio

is 1 for the engine.

16) Draw the typical scramjet engine and explain its working. Discusstypical variations of P and T along this engine

17) A super sonic ramjet consist of a diffuser constant diametercombustion chamber and a convergent nozzle discharging at sonic exit

velocity .for the given data estimate (i)the combustion chamber

diameter(ii)the thrust produced .assume the appropriate ratio of specific

heat at each stage data inlet diameter =75mm inlet Mach no =0.6 at

standard sea level combustion chamber Mach no 0.12 diffuser efficiency

=0.85,nozzle inlet temp =1073k .assume no other losses


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UNI T-3 FUNDAMENTAL OF ROCKET PROPULSION

PART A1) what is the effective jet velocity?2) define divergence factor for conical nozzle3) what is importance of combustion indexn?4) define thrust co efficient5)Define specific impulse6)for what oxidizer-fuel ratio(fuel rich of fuel lean) does the maximum specific

impulse occur?

7) what is meant by chocking in flow through nozzle8)A rockets flight velocity is different from its exhaust velocity. True or

False?Justify your answer.

9) What is relationship between the specific impulse of a propellant and theexhaust velocity of the rocket?

10) Define and write the equation of specific impulse and specific thrust?11) What is super critical nozzle and subcritical nozzle?12) Define specific impulse?13) Define thrust coefficient?14) What is the use of conical nozzle?15) Define the velocity correction factor?16) Define specific impulse of rocket?17) Mention any characteristics of rocket engine which is not posses by

air breathing engine.

18) For what oxidizer- fuel ratio (fuel rich or fuel lean) does the maximumspecific impulse occur.

19)

What are the issue in supersonic air breathing propulsion?20) What happens in the combustion chamber of a liquid rocket?21) State the difference b\w optimum length with characteristics length for

combustion chamber?

22) Define ISP and characteristic exhaust velocity of a propellant?23) What is altitude adapted nozzles?


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PART B

1)Briefly discuss the uniqueness of rocket propulsion. how would you classifychemical rockets? Also compare there performance and application areas.

2)How is the chemical energy of the propellants utilized for propulsive powerof a rocket vehicle? How would you define propulsive efficiency, thermal

efficiency and over all efficiency? briefly discuss.

3) What are the function of an injector in a liquid propellant rocket engine?show that various types of injector used, and briefly discuss the design

aspects for selection of a specific type .

4)Derive an expression for thrust of a rocket motor with a convergentdivergent nozzle,having a finite angle of divergence.

5) The inlet condition for the rocket nozzle are given by the totaltemperature=2800k.total pressure=43 bar and the inlet velocity can be

neglected when compared to the nozzle outlet velocity .the nozzle throat

diameter is 5.2cm.estimate the mass flowrate through the nozzle.assuming

optimum expansion at sea level,determine nozzle exit velocity,exit Mach

no.and the thrust developed by the rocket unit.take ratio of specific heat as

1.35.

6) The following data are related to a rocket thrust chamber the chamberpressure and the temperature are Po=12 Mpa and T=2950k.the molecular

weight of the hot gas in the nozzle is 13.4;average specific heat ratio is

1.2.the ambient pressure is 97.5 kpa.the throat diameter of

nozzle=150mm.determinemass Flow rateexhaust

velocityrocket thrustcharacteristics velocity.

7) What are adapted nozzles? Suggest a few Methods of a adapting a nozzle forhigher altitudes.

8) Compare the relative merits of a conical nozzle and a bell-shaped nozzle forrocket propulsion.9)For a solid propellant rocket with a given data calculate (i) mass flow rate

(ii) exit velocity (iii) characteristic velocity and (iv) Specific impulse. Initial

mass 150 kg,Final mass:150kg,burn time:45 sec. Average thrust 90,000N.


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Chamber Pressure:6Mpa,Throat diameter:50mm,and nozzle exit

diameter:250mm.

10) Derive the expression for basic relation of motion by considering 2dfree body force diagram?

11) Explain the following term 1) thrust coefficient 2) exhaust velocity 3)energy and efficiency 4) characteristic velocity

12) Briefly discuss the uniqueness of rocket propulsion. How would youclassify chemical rockets? Also compare their performance and application

areas.

13) How is the chemical energy of the propellants utilized for propulsivevehicle? How would you define propulsive efficiency, thermal efficiency and

overall efficiency? Briefly discuss.

14) Derive an expression for ideal nozzle exhaust velocity. Also list outthe assumptions.

15) An ideal rocket operates at a combustion chamber pressure of3Mn/m^2 and expand to an ambient pressure of 310^4 N/m^2. The specific

heat ratio of the working substances 1.2 and the gas constant the inlet of the

nozzle is 2700 k, determine the velocity at the throat, ideal exhaust velocity

and nozzle expansion ratio.

16) With the help of an example, briefly outline how would you proceed tofind the adiabatic flame temperature and the molecular weight of thecombustion products in a given rocket propellant system.

17) List down the various tests performed on a rocket engine beforeputting it to operational use. Also discuss static tests for rocket systems.

18) List and very briefly explain the methods of cooling adopted for rocketmotors.

19) What do you understand by frozen and equilibrium condition in anozzle flow?

20) The following measurement where made in sea level test of solidpropellant rocket motor Burn rate 40s,inlet mass before test 1210kg,massof

rocket after test 215kg,avg thrust 62250kg,chamber P 7.00MPa, nozzle exit

P .07MPa, nozzle throat dia0.0855m,nozzle exit dia0.2703m


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21) determine mass flow rate actual average exhaust velocitycharacteristics velocity exhaust velocity and ISP for 1000(0.0898MPa) and

25000(0.00255MPa)m altitude .assume an invariant thrust and mass flow

rate negligible short and stop transients

22) List the principle losses to be accounted for the real nozzle?23) Explain the liner aero spike rocket engine with sketches?24) What are the different thrust programs used in rocket?25) What are the tech available for thrust vector control in liquid rocket .

explain any one the them with suitable example

26) Determine the mass flow rate ,exit velocity ,thrust , characteristicsvelocity) Chamber P =15MPa chamber T=2800k ambient P =95MPa

average specify heat ratio=1.2 molecular weight of burnt gases =1.4 throat

diameter =100mm.

Unit- 4 CHEM ICAL ROCKET

Part A


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7) Compare the pressure-feed system of aliquid propellant rocket with theturbo-feed system.

8)Explain the different thrust vector control devices with suitable sketches.9)Explain why the solid propellant grains are given different shapes. Sketch

the frequently employed geometries.

10) A rocket operates at sea-level with a chamber pressure of 150atmospheres and chamber temperature of 2400k. The propellant

Consumption rate is 1.5 kg/s.Assuming the working fluid to have the

properties of air,calculate the ideal thrust and ideal specific impulse.

11) A) With a neat diagram explain solid propellant grain and grainconfiguration

12) Estimate the mass of pressurization gas in liquid propellant system.13) explain liquid propellant properties14) List the types of propellants used for solid, liquid and hybrid rockets

with their performance values.

15) What are called Bi-Propellant rockets? Explain with a neat sketch ofpressure feed -bi propellant system.

16) What are the important criteria for the selection of cryogenicpropellants? Explain

17) With a good sketch explain the turbo pump feed system in a liquidpropellant rocket engine.

18) Give the classification of liquid propellants. Give examples of eachtype and indicate the order of specific impulse for each combination.

19) Write a note on the type of injectors used in liquid rockets and discussthe relative advantages of each type.

20) Explain why a solid propellant in usage does not give the theoreticallyvalue of specific impulse.

21) What are the different burning rates applicable to a solid propellant?

UNIT 5 ADVANCE PROPULSION TECHNIQUE


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PART A

1) what is nozzle less propulsion system?2) what is major dis advantages of nuclear rockets?3) What is possible application of a solar sail?4) What is the Major disadvantages of a nuclear rocket?5)Describe the principle of electric propulsion system with neat

diagram?

6) Write at least six major advantages of ion propulsion?7) Write the classification of concept of electric propulsion?8) What is called ionization potential?9) Write the three ways in which nuclear energy can be used in

rocket propulsion?10)What are the operating problems of nuclear rocket?11)Why are electrical rockets called essentially power limited?12)Electric propulsion system produce very low thrust level and

very high level ISPtrue or false

13)What are composite propellant?14)What is the need for advantage propulsion techniques?

PART B

1) What are the limitations of an electrical rockets propulsion system?whatare the various types of electrical propulsion system?explain one system

with a neat sketch.

2) With a neat sketch explain ion propulsion rocket3)Draw a neat sketch and explain electrical rocket propulsion technique?4) With the aid of neat sketches explain various techniques for thrust vector

control.

5)Discuss ion propulsion technique as a possible option to chemical rockets.

6) What are the methods of cooling a rocket combustion chamber?7)Explain the working of a hybrid rocket with a sketch.8) Give a comparison of solid and liquid propulsion rockets.9)Explain with neat diagram electro thermal thruster.


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propulsion ii qb

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