Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 15

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Total No. of Questions : 09]

B. Tech. (Sem. – 4th)

APPLIED THERMODYNAMICS - II

SUBJECT CODE : ME – 208 (2008 Batch)

 Paper ID : [A0811]

Time : 03 Hours

Instruction to Candidates:

1) Section - A is Compulsory.

2) Attempt any Four questions from Section - B.

3) Attempt any Two questions from Section - C.

Section – A

QI)

a) What do you understand by air injection and solid injection system?

b) What is the purpose of engine testing?

c) Discuss the term squish, swirl.

d) What are the various factors that influence the flame speed?

e) Differentiate between a flywheel and governor.

0 Define the term pressure coefficient, prewhirl.

g) What do you mean by surging and choking?

h) Define effectiveness of regenerator.

i) Define the term take off thrust and propulsive power of jet propulsion

system.

j) What are the various assumptions made in practical cycle analysis in

gas turbines?

Section-B

Q2) Find the air fuel ratio of four stroke, single-cylinder, air cooled engine with

fuel consumption. Time for l0cc as 20.4sand air consumption time for 0.1m3

as 16.3s. the load is 17kg at the speed of 3000rpm. Find also brake specific

fuel consumption in g/k wh and brake thermal efficiency. Assume the density

of air as I .1 .175 g/m³ and specific gravity of fuel to be 0.7. The lower heating

value of fuel is 43MJ/kg and dynamometer constant is 5000.

3) Free air of 30 m3/min is compressed from 101.3kPa to 2.23 bar in roots

blower. Determine the power required and isentropic efficiency.

4) The effective jet exit velocity from jet engine is 2700m/s- The forward flight

velocity is 1350m/s and the air flow rate is 78.6kgis. Calculate a) thrust

b) thrust power c) propulsive efficiency'

5) What is rocket propulsion? Compare the working of liquid and solid propellant

rockets.

Q6) Why non-dimensional parameters are used to predict the performance

characteristics of compressor? Derive these parameters from the concept

of dimensional analysis.

Section - C

7) A centrifugal compressor has to deliver 6kg/s of air with pressure ratio of

4: I at 175OO rpm. Initial conditions are static air at 1 bar and 15˚C. Assuming

an adiabatic efficiency of 78%, ratio of whirl speed to tip speed 0.94 and

neglecting all other losses, calculate the tip speed, diameter and rise in total

pressure. Also, determine the external diameter of eye for which the internal

diameter is 12cm and the axial velocity at inlet is 150m/sec. Assume

c_p=1 .005kJ/kgK and  =1.4

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 14

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Total No. of Questions : 09]

B. Tech. (Sem. – 4th)

APPLIED THERMODYNAMICS - II

SUBJECT CODE : ME – 208 (2008 Batch)

 Paper ID : [ME210]

Time : 03 Hours

Instruction to Candidates:

1) Section - A is Compulsory.

2) Attempt any Four questions from Section - B.

3) Attempt any Two questions from Section - C.

Section – A

Q1)

a) What is the function of carburetor.

b) Explain why the cooling of IC Engine is necessary.

c) Explain the term slip and power input factor as applied to centrifugal

compressor.

d) Explain the phenomenon of 'surging' in a centrifugal compressor.

e) Explain the term polytropic efficiency of compress or (2), | .

f) What advantage is gained by splitting the turbine section of a gas turbine

into two parts, namely compressor turbine and power turbine (3).

g) Compare a gas turbine with a steam turbine (2).

h) Explain the term Octane number (2).

i) Compare gas turbine and reciprocating engine.

j) What is 'Morse Test'.

Section - B

Q2) Draw the valve timing diagram for an average petrol engine. Give reasons for

early opening of exhaust valve and late closing of inlet valves.

Q3) The following data refers to a test on a single cylinder oil engine working on

fbur stroke cycle:

Diameter of-brake wheel = 60 cm; rope dia= 3 cm; the dead load is 25kg,

when the spring balance reading is 5 kg, and the engine is running at400 rcvl

min. The indicator diagram has area : 4 cm²,length : 6cm and spring

stiffness is 12. The fuel consumption is 0.23kglb.h.p.-hr. and the fuel used

has a calorific value 10500 kcal/kg. Taking cylinder bore 10 cm and piston

stroke l5 cm calculate the B.H.P., I.H.P., mechanical and indicated thermal

 of the engine.

Q4) l)describe the function of impeller and diffuser in centrifugal compressor.

Q5)  The centrifugal compressor of a gas turbine requires 3000 H.P. when running

at  16000 rev/minute. The tip diameter of the impeller is 50 cm and the uniform

width of casing of the vortex chamber between impeller and diffuser is 49rn.

Measurements show that static pressure and temperature at a radius of 27

cm are 2.5 kg, /cm and I10"C. The atmosphere in the test house is I

kg,.icn-r2. Assuming slip factor:0.94 and neglecting friction in the vortex

chamber. calculate :

(a) The mass flow l

( b) 'fhe resultant speed at the section given

(c) The total temperature at the section given

tt may be assumed that there is no prewhirl and the conditions in the vaneless

space correspond to those of free vortex.

Q6) An axial compressor has a degree of reaction of 0.5 at the mean radius with

relative air angles of I 30" and l00u at rotor inlet and outlet respectively. The

angles are measured in the same direction from the blade velocity direction.

The overall stagnation pressure ratio is 3.5 and the stagnation isentropic

efficiency is 85% when the inlet stagnation temperature is 330 K. The blade

speed is constant at 200 m/s and the flow velocity is also constant in the

compressor. The work done factor is 0.85. Find the stagnation polytropic

efficiency and .the number of stage.

Section - C

Q7) In a gas turbine plant, air is compressed from atmospheric conditions to the

delivery pressure 4bar and temperature 480 K. In the combustion chamber,

a fuel of calorific value 45000 kJ/kg is injected and combustion takes place at

consmnt pressure. The injection of fuel is so regulated that the air fuel ratio is

60 : I . f,or a mass flow rate of l0kg/s design the turbine e nozzle for throat and

exist areas. The maximum temperature of blades is to be 873 K. Take

c_p =1 .005 kJ/kg and  =1.4 both for air and gases. p

QS) Write a note on any two of the following :

(a) Ramjet

(b) Turbo prop

(c) Supercharging of IC engines

Q9) A four cylinder, four stroke engine is supplied with l5.25 kg of air/kg of octane fuel having heat value 10650 kcal/kg. Calculate (a) the compression

ratio. (b) brake specific fuel consumption, (c) bore and stroke; (d) b.m.e.p.

The following data may be assumed :- air standard efficiency:0.53, relative efficiency : 0.70, mechanical efficiency : 0.g; volumetric efficiency : 0.g; stroke equal 1.25 times the bore ; suction conditions are I kg/cm and 60"C the engine runs at 2400 rev/min and develops 96 brake power.

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 13

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Total No. of Questions : 09]

B. Tech. (Sem. – 4th)

APPLIED THERMODYNAMICS - II

SUBJECT CODE : ME – 208 (2008 Batch)

 Paper ID : [A0811]

Time : 03 Hours

Instruction to Candidates:

1) Section - A is Compulsory.

2) Attempt any Four questions from Section - B.

3) Attempt any Two questions from Section - C.

Section – A

QI) eox2=20)

a) What do you understand by octane and cetane number rating of fuel.

b) What are the objectives of supercharging the IC engines.

c) Explain why aerofoil blading is needed in axial flow compressors?

d) What is delay period and what are the factors that affect delay period.

e) SI engines are quantity governed while CI engines are quality governed.

Explain. D For the given air flow and pressure ratio the vane type blower needs less work than a roots blower. Give reasons.

g) Define the term slip factor, power input factor.

h) Write down the methods of cooling the turbine blades.

t) Define the term thrust, thrust power of jet propulsion system.

j) State the assumptions made in an ideal cycle analysis of gas turbines.

Section - B

Q2) A six-cylinder gasoline engine operates on four stroke cycle. The bore of each

cylinder is 80 mm and the stroke is 100 mm. At speed Of 4000 rpm the fuel

consumption is 20 kg/hr and the torque developed is 150 Nm. Calculate (i) the

brake power (ii) the brake mean effective pressure (iii) brake thermal efficiency

if calorific value of the fuel is 43000 kJ/kg.

Q3) Discuss the working of vane type blower with neat sketch.

Q4) With the aid of neat diagram, explain the working principle of ramjet engine.

Q5) A flying turbojet engine propels at speed of 880 km/hr and draws air at the rate of 50 kg/s. Isentropic enthalpy drop in the nozzle is 190 kJ/kg and its velocity

coefficient is 0.96. Fuel air ratio used is 0.012. The calorific value of fuel used

is 46000 Kj/kg and combustion efficiency is 95Vo. Find thermal, propulsive

and overall efficiency.

Q6) Define polytropic efficiency of compressor with the help of T-S diagram and

obtain an expression for polytropic efficiency.

Section - C

Q7) A centrifugal compress runs at 16000 rpm and power required to run the

compressor amounts to 2300 kW. The outer diameter of the impeller is 50 cm.

The uniform width of the casing of vortex chamber between impeller and

diffuser is 4 cm. Static conditions at a radius of 27 cm were measured and

it were equal to 2.4 bar and 390 K. Surrounding pressure is lbar. Assuming

slip factor of 0.94, find the mass flow rate of gas, the resultant velocity

and temperature at the given radius of 27 cm. Assume c_p = 1.005 kJ/kgK and

 = 1.4

Q8) The first stage of an axial compressor is designed on free vortex principles,

with no on let guide vanes. The rotational speed is 6000 rpm and the stagnation

temperature rise is 20K. The hub-tip ratio is 0.60, work done factor is 0.93 and

isoentropic efficiency of the stage is 0.89. Assuming an inlet velocity of 140

m/s and ambient conditions of 1.01 bar and 288 K, calculate (i) tip radius and

corresponding rotor air angles, if the Mach number relative to the tip is limited

to 0.95 (ii) mass flow entering the stage (iii) stage stagnation pressure ratio and

power input (iv) rotor air angles at the root section. Assume cp = 1.005 kJ/kgK

and  = I.4.

Q9) In a gas turbine power plant the temperature ratio T_max/ T_min,in is fixed as 4. The system has compression in two stages with perfect intercooling in between the

stages followed by single stage expansion in gas turbine. Isoentropic efficiency

of each compressor and turbine is 0.85 and 0.9 respectively. Minimum

temperature of the cycle is 300K. Assuming the pressure ratio of the cycle as

6. Find the network output, heat input and thermal efficiency of the cycle.

Take P_min = P₁, = 1 bar, c_p = 1.005kJ/kgK and   = l-4.

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 12

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Total No. of Questions : 09]

B. Tech. (Sem. – 4th)

APPLIED THERMODYNAMICS - II

SUBJECT CODE : ME – 208 (2008 Batch)

 Paper ID : [A0811]

Time : 03 Hours

Instruction to Candidates:

1) Section - A is Compulsory.

2) Attempt any Four questions from Section - B.

3) Attempt any Two questions from Section - C.

Section – A

Q1)

a) What is pseignition?

b) How I.C. engines are classified?

c) What is an axial flow compressor?

d) What is meant by chocking in centrifugal compressor?

e) How blade materials for a gas turbine is selected?

fl Define specific fuel consumption.

g) What is a turbojet engine?

h) Define angle of attack.

i) What do you understand by delay period in S.I engine?

j) What are the advantages of super charging'?

Section - B

Q2) Discuss the effect of detonation on engine performance.

Q3) During testing of a four  stroke diesel engine  the following  observations

were noted :

Area of indicator diagram = 420mml

Length of indicator diagram = 62mm

Spring number = l.l bar/mm.

' Diameter of piston = l00mm

Length of the stroke = l50mm

Engine speed = 450 rpm.

Determine the indicated mean effective pressure and indicated power.

Q4) Compare and contrast the rotary compressor and reciprocating compressor.

Q5) Explain the effect of prewhirl on the impeller of centrifugal pump.

Q6) What do you understand by propulsion system? Discuss the advantages

and disadvantages of jet propulsion system.

Section - C

Q7) A centrifugal compressor delivers 50 kg of air per minute at a pressure of 2

bar and 97"C. The intake pressure and temperature of the air is I bar and

l5'C. If no heat is lost to the surrounding find :

(a) Index of compression.

(b) Power required if the compression is isothermal.

Take R=287Jlkgk.

8. a simple closed cycle gas turbine plant receives air at 1 bar and 15 C and compressor it to 5 bar and then heats it to 800 C in the heating chamber. The hot air expands in a turbine back to 1 bar. Calculate the power developed per kg. of air supplied per second. Take Cp for air as 1kj/kgk.

9. Write notes on:

`        a. High speed engine indicators.

          b. Surging in axial flow compressor 

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 11

Applied Thermodynamics-II

(ME-210, MAY 2007)

Time: 3 Hrs

Max Marks: 60

Note: Section A is compulsory. Attempt any four questions from section B and any two from  Section C.

Section-A

1.

 a) What is compression ratio?

b) What is knocking?

c) What is surging in compressor?

d) What is slip factor?

e) What is Prewhirl?

f) What is chocking?

g) What is diffuser efficiency?

h) What is regeneration?

i) Write the name of two solid propellants?

j) What is Ram jet?

Section-B

2. Compare ‘air swirl’ in CI engines with ‘turbulence’ in SI engines.

3. What is the basic difference in the combustion process of SI and CI engines?

4. The first stage of an axial flow compressor is to be designed for an axial velocity of 133  m/s, mass flow of air 22.7 kg/s and for ambient conditions of 1 kgf/cm2

 and 10º C.  5. A gas turbine plant works between the temperature limits of 1152º K and 288º K,  isotropic efficiencies for compressor and turbine are 0.85 and 0.8 respectively. Determine  the optimum ratio for maximum work output and also for maximum cycle thermal  efficiency.

6. Derive an expression for the optimum pressure ratio giving maximum specific output in  simple cycle gas turbine.

Section-C

7. Differentiate between centrifugal and axial compressor? Define dimensionless parameters  such as flow coefficient, pressure coefficient and reaction.

8. a) A rotary vane compressor works between the pressure limits of 1 kgf/cm²

 and 1.5  kgf/cm2  and gives 4m3/min of free air delivered when running at 200 rpm. Determine the  horse power required to drive the compressor when ports ar so placed that there is no  internal compression.

b) State merits and demerits of closed cycle gas turbine over open cycle.

9. a) Air enters at the rate of 900 kg/min into a compressor of jet aircraft traveling at 241 m/s.  the air-fuel ratio is 60:1 and the compression pressure ratio is 6:1. The calorific value of  the fuel is 10,000 kcal/kg. Neglecting all losses, calculate the thrust, the specific fuel  consumption and propulsive efficiency.

b) Explain the principle of jet propulsion.

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 10

Applied Thermodynamics-II

(ME-210, Dec-07)

Note: Section A is compulsory. Attempt any four questions from Section B and any two from  Section C.

Section-A

1.

a) What is Supercharging?

 b) What is octane number?

 c) What is polytrophic work?

 d) What is turbojet engine?

 e) What is stalling?

 f) What is propulsion Efficiency?

 g) Draw Brayton cycle.

 h) Define turbine efficiency.

 i) Why intercooling is done?

 j) What is Turbojet?

Section-B

2. What are the three methods of generating swirl in CI engine combustion chamber?

3. Explain the stages of combustion in a CI engine.

4. A gas turbine plant works between the fixed adiabatic temperature limits 3000°K and 900°K,  the absolute pressure limits being 1 kgf/cm2  and 4kgf/cm2. The isentropic efficiency of the  blower is 0.8 and that of turbine is 0.85. Estimate the actual thermal efficiency of the plant.  Calorific value is 10,000 kcal/kg.

5. The air enters the compressor of a gas turbine at atmospheric pressure and 30°C and is  compressed to 6kgf/cm2 with an isentropic efficiency of 85%. The turbine inlet temperature is  500°C. The isentropic efficiency of the turbine is 80%. Estimate the flow of air in kg/s for a net  h.p. of 2000.

6. What are the various methods which are used to improve the efficiency and output of a gas  turbine?

Section-C

7. Explain the working principle of centrifugal compressor with the help of h-s chart. What do you  mean by diffuser efficiency?

8. (a) The following data are given for a centrifugal compressor and it is required to find the  impeller tip diameter:

 N = 1500 rpm, G=22.5 kg/sec, Ambient temperature = 21°C, Atmospheric pressure = 1  kgf/cm² , pressure ratio = 4, adiabatic efficiency = 0.76, Double side impeller, slip factor = 0.9,  work input factor = 1.04. Assume inlet velocity of flow = exit flow from diffuser = 140 m/s.

 (b) Discuss the surging in the case of centrifugal and axial flow compressor.

9. (a) Air at temperature of 15°C enters a gas turbine plant working at pressure ratio of 5.  Turbine inlet temperature is 800°C. Polytropic efficiency of compressor and turbine is 0.87.  Assume cp = 0.24 for air and gases and calorific value of fuel used = 10,000 kcal/kg of fuel.

Calculate overall efficiency and specific output.

 (b) Differentiate between reciprocating and rotary compressor.

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 9

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B. TECH (IE, ME) (Sem.-4th)

APPLIED THERMODYNAMICS-II

Subject Code: ME-208

Paper ID: [A0811]

Time: 3 Hrs.

INSTRUCTIONS TO CANDIDATE:

1. Section-A is compulsory.

2. Section-B Attempt any four questions.

3. Section-C Attempt any two questions.

                                                SECTION-A

1.      

a.     What is a four stroke engine?

b.     What is preignition?

c.      What is cetane number?

d.     What is the function of rotary compressor?

e.      What is degree of reaction?

f.       Define coefficient of lift.

g.     What is meant by choking in compressor

h.     What do you understand by operating variables?

i.       Define thrust power

j.       What is an engine indicator?

Section-B

2.     Differentiate between preignition and detonation in S.I. engine.

3.     Explain the phenomenon of surging in rotary compressor.

4.     An uncooled centrifugal compressor running at 15000 r.p.m sucks in air at 290 K axially into the eye of its impeller. The air leaves the impeller with a whirl velocity which equals 0.85 times the velocity of the blade tip. The blade tip has an outer diameter of 40 cm. if the isentropic efficiency of the compressor is 0.75. calculate.

a.     The rise in temperature of air compressed and

b.     The static head pressure ratio of the com pressor. The kinetic energy of air at outlet from the compressor is equal to that at inlet to the impeller.

5.     Discuss the means of improving the efficiency and specific output of a gas turbine  working on simple Brayton cycle.

6.     State the difference between jet propulsion and rocket propulsion system.

Section –C

7.     An ‘axial flow compressor with compression ratio as 5 m draws air at 20 C delivers  it at 50 C. assuming 50% degree of reaction, find the velocity of flow if the blade velocity 100m/s. also find the number of stages. Take work factor = 0.85, a= 10 B=40 and Cp = 1kj/kg K.

8.     Derive an expression for the thermal efficiency of a gas turbine plant and show that it is independent of the mass of air circulated in it.

9.     Discuss the effect of various engine parameters on detonation in diesel engine.,   

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 8

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B. TECH (IE, ME) (Sem.-4th)

APPLIED THERMODYNAMICS-II

Subject Code: BTEE 404

Paper ID: [A1214]

Time: 3 Hrs.

INSTRUCTIONS TO CANDIDATE:

1.     Section A is compulsory consisting of ten questions carrying two marks each

2.     Section-B contains five questions carrying five marks each and st6u8dents have to attempt any four questions

3.     Section –C contains three question carrying ten marks each and students have to attempt any two questions

1.       

a.     What is cycle air rate.

b.     Define co- efficient of lift and drag

c.      What is degree of reaction.

d.     Define Stagnation pressure

e.      Define optimum pressure ratio.

f.       What is thermal efficiently?

g.     Explain the principle of jet propulsion

h.     Define ‘Best value of index.

i.       What is necessity of inter- cooling in compressor?

j.       Explain the working of vane type blower.

Section –B

2.     Derive the expression for the volumetric efficiently of a reciprocating air compressor in terms of clearance ratio, pressure ratio and index of the compression.

3.     A three stage compressor takes in air at rate of 0.25 m3/s at 1 bar and 298K. the pressure and temperature before compression is 1 bar and 308 K and the index of compression is 1.25. find inter cooler pressures and the minimum power required to run the  compressor, if the delivery pressure is 35 bar. Neglect the clearance.

4.     A centrifugal compressor receive air at 1 bar and delivers it at 3.5 bar. Find the final temperature of air if the initial temperature of air is 310K. the compressor compresses 2 kg of air per second.

5.     Derive the expression for the pressure ratio in each stage of multi stage axial flow air compressor

6.     Derive an expression for the optimum pressure ratio, for the maximum net work output, in a Brayton cycle. What is the corresponding cycle efficiency?  

7.     An axial flow compressor, with compression ratio as 4 , draws air at 20 C and delivers it at 197 C the mean blade speed and flow velocity are constant throughout the compressor. Assuming 50 % reaction blading and taking blade velocity as 180 m/s, find the flow velocity and the number of stages if work factor = 0.85, a = 2 B= 2 and Cp = 1.005 kj/kg K.

8.     A rotary air compressor working between 1 bar and 2.5 bar has internal and external diameter of impeller as 300 mm and 600 mm respectively. The vane angle at inlet and outlet are 30 and 45 respectively. If the air enters the impeller at 15 m/s find  i) speed of the impeeler in rpm ii) work done required by the compressor.

9.        

a.     Define thrust on a rocket. Derive an expression for the net thrust.

b.     Draw the neat sketch of liquid propellant engine and explain the general working.

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Total No. of Questions : 09]

B. Tech. (Sem. – 4th)

APPLIED THERMODYNAMICS - II

SUBJECT CODE : ME – 208 (2008 Batch)

 Paper ID : [A0811]

Time : 03 Hours

INSTRUCTION TO CANDIDATES :

1. SECTION-A is COMPULSORY consisting of TEN questions carrying

TWO marks each.

2. SECTION-B contains FIVE questions carrying FIVE marks each and

students has to attempt any FOUR questions.

3. SECTION-C contains THREE questions carrying TEN marks each and

students has to attempt any TWO questions.

SECTION-A

l. Answer briefly :

a. What is engine indicator? What function does it perform in IC engine?

b. What is octane number?

c. What is specific fuel consumption? How do we evaluate it?

d. Why do we do supercharging in IC engines?

e. Write the expression for pressure rise in case of axial flow compressor.

f. Define for compressors isothermal, isentropic and polytropic efficiency.

g. What are the advantages of closed cycle gas turbine over the open

cycle gas turbine?

h. What is the use of pre-whirl in case of compressors?

i. What are various fuels used for in rocket motors? What are the

desirables from them?

j. What is the difference between ram jet engine and the pulse jet

engine?

SECTION-B

2. Explain the phenomenon of knocking in CI engine. What are different

factors those influence knocking? Describe the methods to suppress it.

3. What is the criterion for selection of blade materials in case of gas

turbines? What are different blade materials? Also, discuss the turbine

blade cooling requirements.

4. Draw the valve-timing diagrams for four stroke petrol engine and four

stroke diesel engine and discuss the various cut off points.

5. Derive the expression for pressure rise per stage for axial flow compressor

clearing showing the velocity triangles ant inlet and outlet. Also represent

the compression process on the T-s diagram.

6. Derive expressions for thrust power, propulsion energy, propulsion and

thermal efficiencies for a propulsive system.

SECTION-C

7. A centrifugal compressor is desired to have a total pressure ratio of

3.5:1. The inlet eye of the compressor impeller is 30 cm in diameter. The

axial velocity at the inlet is 130 m/s, and the mass flow is 10 kg/s. the

velocity in the delivery duct is 115 m/s. the tip speed of the impeller is

450 m/s and runs at 16,000 rpm with the total isentropic efficiency of

78% and pressure coefficient of 0.72. The ambient conditions are

1.013 bar and 15°C. Calculate :

a) the static pressure ratio.

b) the static pressure and temperature at the inlet of compressor.

c) work of compressor per kg of air.

d) the theoretical power required.

8. In a gas turbine installation, air is taken in LP compressor at 288 K and

1.1 bar and after compression, it passed through intercooler where its

temperature is reduced to 295 K. The cooled air is further compressed in

IP unit and passed in the combustion chamber where its temperature is

increased to 950°C by burning the fuel. The combustion products expand

in HP turbine which runs the compressor and further expansions is continued

in LP turbine which runs the alternator. The gases coming out from

LP turbine are used for heating the incoming air from IP compressor and

then exhausted to atmosphere. Taking the following data determine the

power output, specific fuel consumption and thermal efficiency. Pressure

ratio of each compressor = 2, isentropic efficiency of each compressor

stage = 85%, isentropic efficiency of each turbine stage = 85%, effectiveness

of heat exchanger = 0.75, air flow = 15 kg/s, CV of fuel = 45 MJ/kg.

Cp (air) = 1 kJ/kgK, Cp (gas) = 1.15 kJ/kg K,  (air) = 1.4,

 (gas) = 1.33. Neglect the mechanical pressure, pressure and heat

losses of the system and fuel mass ratio.

9. Following data were observed from the trial of oil engine. BHP of the

engine = 73.55 kW, oil consumption = 16.5 kg/hr, oil fuel contains

84% C and 16% H2, CV of the oil = 45.2 MJ/kg. The cooling water

after passing through the cooling jacket is further passed through the

exhaust gas calorimeter. Cooling water flow rate = 1220 kg/hr, temperature

of the water entering the-cooling jacket = 18°C, temperature of the water

leaving the jacket = 57°C, temperature of the water leaving the exhaust

gas calorimeter = 82°C, temperature of the exhaust gases leaving the

calorimeter = 100°C, temperature of the exhaust gases leaving the

engine = 410°C. Engine room temperature = 18°C. Specific heat of

exhaust gases = 1.0035 kJ/kg K. Find the excess air supplied to the

engine. Also draw heat balance sheet on minute and % basis.

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 6

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Total No. of Questions: 09

B. Tech. (ME) (Sem.-4th)

APPLIED THERMODYNAMICS - I

Subject Code: BTME-404

Paper ID: [A1214]

Time: 3 Hrs.

INSTRUCTION TO CANDIDATES :

1. SECTION-A is COMPULSORY consisting of TEN questions carrying

TWO marks each.

2. SECTION-B contains FIVE questions carrying FIVE marks each and

students has to attempt any FOUR questions.

3. SECTION-C contains THREE questions carrying TEN marks each and

students has to attempt any TWO questions.

SECTION-A

l. Answer briefly :

(a) What are the advantages of multi-stage compression?

(b) State at least four applications of compressed air.

(c) List the positive displacement type rotary compressors.

(d) Write the steady flow energy equation & explain various terms?

(e) Explain the terms pre-whirl & slip factor.

(f) Explain the term surging used in centrifugal compressors.

(g) What is stalling in case of axial flow compressor?

(h) List the different components of axial flow compressor.

(i) What is semi-closed gas turbine ?

(j) Name the two solid propellants used in rockets.

SECTION-B

2. Show that the optimum intermediate pressure of a two-stage compressor

for minimum work is the geometric mean of the suction & discharge

pressures.

3. Define degree of reaction as applied to axial flow compressor and show

that the blades are symmetrical for 50% reaction.

4. Explain the function of impeller and diffuser in the centrifugal compressor.

5. Discuss the methods of improving the work ratio, specific, output & cycle

thermal efficiency by employing multi-stage system gas turbines with

intercooling and reheating.

6. Discuss advantages and disadvantages of Jet propulsion system over

other propulsion system.

SECTION-C

7. A single cylinder double acting reciprocating compressor compresses

3 kg/min of air. From 1 bar, 300 k to 6 bar. The clearance volume is

such that the maximum pressure at the end of compression cannot exceed

15 bar. Calculate the power input, the volumetric efficiency & the cylinder

dimensions, when the compressor runs at 300 r.p.m. The index of compression

& expansion is equal to 1.3 & stroke/bore ratio is 1.5.

8. In an oil gas turbine installation, ambient pressure is 1 bar & 300 K &

compressed to a pressure of 4 bar. The oil with a calorific value of

42000 KJ/kg is burnt in the combustion chamber to raise the temperature

of air to 550°C. If the air flows at the rate of 1.2 kg/s; Find the net

power of the installation. Also find air fuel ratio. Take Cp=1.05 KJ/kg-K.

9. (a) Explain the working difference between propeller-jet, turbo-jet and

turbo-prop.

(b) Explain the advantages of dual turbine system.

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 5

Roll No. ......................

Total No. of Questions : 09]

B. Tech. (Sem. – 4th)

APPLIED THERMODYNAMICS - II

SUBJECT CODE : ME – 208 (2008 Batch)

 Paper ID : [A0811]

Time : 03 Hours

Instruction to Candidates:

1. SECTION-A is COMPULSORY.

2. Attempt any FOUR questions from SECTION-B.

3. Attempt any TWO questions from SECTION-C.

SECTION-A

l. Write short notes on :

(a) What is pre ignition ?

(b) What is centane number ?

(c) Explain the term supercharging.

(d) What do you mean by surging & choking ?

(e) Define degree of reaction for axial flow compressors.

(f) Explain the term pre whirl.

(g) Enumerate the various uses of gas turbines.

(h) Define the term thrust and thrust power of jet propulsion system.

(i) Write the name of two solid propellants.

(j) What are the advantages of multi-stage compression?

SECTION-B

2. Explain the phenomenon of knock in Combustion Ignition Engine &

compare it with SI engine knock.

3. Explain the function of impeller & diffuser used in a centrifugal compressor.

4. Show that axial flow compressor with 50% reaction has symmetrical

bladings.

5. Explain the fundamental difference between the Jet propulsion & Rocket

propulsion.

6. State the merits & demerits of closed cycle gas turbine over open cycle

gas turbine.

SECTION-C

7. (a) What is delay period and what are the factors that affect the delay

period ?

(b) What are the various characteristics of an efficient cooling system ?

8. In a gas turbine plant working on the Pnayton cycle with a regenerator of

75% effectiveness, the air at the inlet to the compressor is at 1 bar,

30°C, the pressure ratio is 6 and the maximum cycle temperature is

900°C. If the turbine and compressor have each an efficiency of 80%,

find the percentage increase in cycle efficiency due to regeneration.

9. A centrifugal compressor has an inlet eye 150 mm diameter. The impeller

revolves at 20,000 rpm and the inlet air has an axial velocity of 107 m/s,

inlet stagnation temperature 294 K and inlet pressure 1·03 bar. Determine:

(a) Theoretical angle of the blade at this points and

(b) Mach number of the flow at the tip of the eye. 

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 4

Roll No.

B. TECH (IE, ME) (Sem.-4th)

APPLIED THERMODYNAMICS-II

Subject Code: ME-208

Paper ID: [A0811]

Time: 3 Hrs.

INSTRUCTIONS TO CANDIDATE:

1. Section-A is compulsory.

2. Section-B Attempt any four questions.

3. Section-C Attempt any two questions.

                                                SECTION-A

Q. 1.(a) What do you understand by term detonation?

(b) What is meant by delay period?

(c) What are different types of supercharger?

(d) How rotary compressors are classified?

(e) Define slip factor.

(f) Define angle of attack.

(g) What is surging in axial flow compressor?

(h) How gas turbine differs from steam turbine?

(i) What is the principle of Jet propulsion?

(j) What is a turbojet engine?

                                                Section-B

Q. 2. Discuss the effect of detonation on engine performance.

Q. 3. Derive an expression for efficiency of roots blower in terms of pressure ratio and ratio of specific heats.

Q. 4. A centrifugal compressor delivers 0.5 kg of air per second at a pressure of 1.8 bar and

1000C. The intake conditions are 200C and 1 bar. Find the isentropic efficiency of the

compressor and the power required to drive it. Take n = 1.65 and CP = 1 kJ/kg K.

Q. 5. Differentiate between a closed cycle gas turbine and an open cycle gas turbine.

Q. 6. Describe the principle of working of a turboprop engine.

                                                Section-C

Q. 7. Discuss briefly different methods of governing of I C engine.

Q. 8. A rotary air compressor receives air at a pressure of 1 bar and 170C, and delivers it at a pressure of 6 bar. Determine, per kg of air delivered, work done by the compressor and  heat exchanged with the jacket water when the compression is isothermal, isentropic and by the relation pv1.6=constant.

Q. 9. A gas turbine plant consists of two stage compressor with perfect intercooler and a single stage turbine. If the plant works between the temperature limits of 300 K and 1000 K and pressure limit of 1 bar and 16 bar, find the net power of the plant per kg of air. Take specific heat at constant pressure as 1 kJ/kg K.

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 3

Roll No.

Total No. of Questions: 09

B. Tech. (ME) (Sem.-4th)

APPLIED THERMODYNAMICS - I

Subject Code: BTME-404

Paper ID: [A1214]

Time: 3 Hrs.

INSTRUCTIONS TO CANDIDATE:

1. Section-A is compulsory.

2. Attempt any four questions from Section-B.

3. Attempt any two questions from Section-C.

SECTION–A

Q1. Write briefly:

a) How will you classify the air compressor?

b) Define the term “Compressor capacity”.

c) What is the difference between a rotary and a reciprocating compressor?

d) Write the steady flow energy equation for a compressor.

e) What is slip as applied to compressors.

f) Define the term surging.

g) Why is the pre guide vanes provided in a centrifugal compressor?

h) State the principle of jet propulsion.

i) List he methods of thermal refinement for a gas turbine cycle

j) Define the term “work ratio’ for a gas turbine.

SECTION-B

Q2. In a two stage air compressor in which the intercooling is perfect. prove that the work

done in compression is minimum when the pressure in the intercooler is geometric mean

between initial and final pressures.

Q3. Explain the phenomenon of surging and chocking in a centrifugal compressor.

Q4. With the help of a neat sketch discus the working of a vane blower compressor.

Q5. Discus in details different methods of improving the efficiency and specific output of a simple gas turbine.

Q6. The following data refers to a turbo-jet flying at an altitude of 950m:

sped of turbojet=80km/hr

Propulsive efficiency=5%

Overall efficiency of the turbine plant=17%

Density of air at 950m altitude=0.17kg/m3

Drag on the plane=610N

Assuming the calorific value of fuel as 4600kj/kg calculate (i) Absolute velocity of the jet (i) Volume of air compressed per min (i) Diameter of jet (iv) Power output of Unit

SECTION-C

Q7. A centrifugal compressor compressed 4.8m3/s of air from 1 bar and 20oc to 1.5 bar. The index of compression n is 1.5. The flow velocity at inlet and outlet of the machine is the

same and equal to 65m/s. The inlet and outlet impeller diameters are 0.32m and 0.62m respectively. The blower rotates at 800 r.p.m. Calculate: (i) The blade angles at inlet and outlet of the impeller (i) The breadth of blade at inlet and outlet. It may be assumed that no diffuser is employed and al the pressure increase takes place in impeller and blades have negligible thickness. Q8. In an air-standard regenerative gas turbine cycle the pressure ratio is 5. Air enters the compressor at 1 bar, 30 K and leaves at 490 K. The maximum temperature in the cycle

is 100K. Calculate the cycle efficiency given that the efficiency of the regenerator and the adiabatic efficiency of the turbine both are 80%. Take γ=1.4 for air.

Also draw the T-s diagram for the cycle

Q9. A multi-stage axial flow compressor delivers 20kg/s of air. The inlet stagnation

condition is 1 bar and 17oC. The power consumed by the compressor is 4350KW.

Calculate (i) Delivery pressure (i) Number of stages (i) Overall isentropic efficiency of the compressor. Assume temperature rise in the firsts stage is 15oC, the polytrophic efficiency of compression is 8% and the stage stagnation pressure ratio is constant.

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 2

Roll No. ......................

Total No. of Questions : 09]

B. Tech. (Sem. – 4th)

APPLIED THERMODYNAMICS - II

SUBJECT CODE : ME – 208 (2008 Batch)

 Paper ID : [A0811]

Time : 03 Hours

Instruction to Candidates:

1. SECTION-A is COMPULSORY consisting of TEN questions carrying

TWO marks each.

2. SECTION-B contains FIVE questions carrying FIVE marks each and

students has to attempt any FOUR questions.

3. SECTION-C contains THREE questions carrying TEN marks each and

students has to attempt any TWO questions.

SECTION-A

l. Answer briefly :

(a) What is delay period and what are the factors that affect the delay

period ?

(b) What is the need of supercharging in I.C. Engines ?

(c) List the positive displacement type compressors of rotary type.

(d) Define prewhirl. Explain its effect on the impeller of a centrifugal

compressor.

(e) Explain the terms : mean effective pressure & swept volume used in

case of internal combustion engines.

(f) Explain the terms slip factor and power input used in case of centrifugal

compressor.

(g) What are the factors that affect the performance of axial flow

compressor ?

(h) Write the field of applications of axial flow compressors.

(i) Differentiate between closed & semi-closed gas turbines.

(j) State the fundamental difference between the Jet propulsion & Rocket

Propulsion

SECTION-B

2. Bring out clearly the process of combustion in C.I. engines & also

explain the various stages of combustion.

3. Describe the phenomenon of detoriation in C.I. engines. On what factors

does detoriation depend ?

4. Describe the function of impeller and diffuser in a centrifugal compressor.

5. Draw the velocity triangles for hub, mean and tip radius for free vortex

conditions.

6. Discuss briefly the methods employed for improvement of thermal efficiency

of open cycle gas turbine plant.

SECTION-C

7. A gas turbine unit receives at 1 bar and 300 K and compresses it

adiabatically to 6·2 bar with efficiency of the compressor 88%. The fuel

has a heating value of 44180 kJ/kg and the fuel/air ratio is 0·017 kg fuel/

kg air. The turbine internal efficiency is 90%, calculate the compressor

work, turbine work and thermal efficiency.

8. Explain with neat sketch working of an Axial flow compressor. How does

it differ from centrifugal compressor ?

9. A centrifugal compressor with an overall diameter of 1 m runs at 5000

r.p.m. Air is supplied to the centrifugal compressor at 20°C and 100 kPa.

The mass flow rate of air is 25 kg/s. Isentropic pressure ratio is 2·5.

Calculate :

(a) Isentropic efficiency

(b) The rotor power

(c) The shaft power.

Assume slip factor of 0·9

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Applied Thermodynamics - II, Question Paper of Mechanical Engineering 4th Semester, Download Question Paper Applied Thermodynamics 1

Roll No. ......................

Total No. of Questions : 09]

B. Tech. (Sem. – 4th)

APPLIED THERMODYNAMICS - II

SUBJECT CODE : ME – 208 (2008 Batch)

 Paper ID : [A0811]

Time : 03 Hours

Instruction to Candidates:

1) Section - A is Compulsory.

2) Attempt any Four questions from Section - B.

3) Attempt any Two questions from Section - C.

Section – A

Q1)

 a) How is compression ratio of an S.I. engine fixed?

 b) What is pre-ignition?

 c) Explain the term prewhirl used in centrifugal compressor.

 d) Define slip factor & pressure coefficient in the centrifugal compressor.

 e) Define degree of reaction.

 f) Explain the phenomenon of stalling in an axial flow compressor.

 g) State the assumptions made in an ideal cycle analysis of gas turbines.

 h) What is the difference between turbine blade and compressor blade.

 i) Define the term thrust and thrust power of jet propulsion system.

 j) Explain the principle of jet propulsion.

Section – B

Q2) Explain the effect of super charging of an I.C. Engine.

Q3) Explain the method to calculate the blade angle at the impeller eyeroot and the eye tip.

Q4) Explain briefly the design and off-design characteristics of an axial flow compressor.

Q5) Why are regenerators and intercoolers used in air craft engines?

Q6) Discuss the effect of compression ratio and air-fuel-ratio on the power and efficiency  of a petrol engine.

Section – C

Q7) The ambient conditions at inlet at 20ºC and 1 bar. At exit the total head temperature

and pressure are 150ºC and 3.5 bar, and static pressure at exit is 3 bar. Calculate

 (a) The Isentropic efficiency.

 (b) The polytropic efficiency.

 (c) The air velocity at exit.

Q8) In a gas turbine plant on the Brayton cycle the air at the inlet is 27ºC, 1 bar. The

pressure ratio is 6.25 and the maximum temperature is 800ºC. The turbine and

compressor efficiencies are each 80%. Find

 (a) The compressor work per kg of air.

 (b) The turbine work per kg of air.

 (c) The heat supplied per kg of air.

 (d) The cycle efficiency.

 (e) The turbine exhaust temperature.

Q9) (a) Explain the operation of a propeller. What is an athodyol? What is rocket.

(b) A turbojet flying at 850 km/hr has an air mass flow rate of 50 kg/s. The enthalpy

drop across the nozzle is 200 kJ/kg and the nozzle efficiency is 0.9. The air fuel

ratio is 80 and the heating value is 40 MJ/kg. Estimate the propulsive power,

thrust power, propulsive, thermal & overall efficiency of the unit. 

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