Janardan Rai Nagar Rajasthan Vidyapeeth 2006 B.Tech Aeronautical Engineering THERMODYNAMICS - exam paper

Model Question Paper

BSAE2-BSCH2-BSE2-BSMR2-BSM2-BSAE7-BSCH7-BSMR7-BSM7- THERMODYNAMICS

Time : 3 hrs Maximum marks : 75

 

Instruction:

1. Question paper is divided into Group A, Group B and Group C

2. Each Group is 25 Marks

3. Figure to the right in bracket indicates marks.

4. Good Handwriting is expected

5. Assume suitable data if necessary.

 

Group A (25 Marks)

 

Answer any three questions (Question 1 is compulsory)

	(5)

 

Q.1 Explain the method of determining the indicated power of a multi-cylinder engine

without using an indicator.

(10)

Q.2 Air at 1 bar and 30⁰C is to be compressed to 1.2 bar at the rate of 50m³/min. Find

(10)

the power required by a Roof s blower.

Q.3 Explain the working of Modern Carburetor ?

(10)

Q.4 Air at 1 bar and 30^o C is to be compressed to 1.2 bar at the rate of 50 m³/min.

Find the power required by a Roofs blower

(10)

Q.5 The following data refer to a test on a petrol engine: Indicated power = 30kW;

Brake power = 26; Engine speed = 1800 rpm; Fuel per brake power hour =0.35 kg;

Calorific value of the fuel used = 44 100 kJ/Kg

Group B (25 Marks)

 

Answer any three questions (Questions 6 is compulsory)

(5)

Q.6 Differentiate between petrol and diesel engine.

(10)

Q.7 Air at 1 bar and 30^o C is to be compressed to 1.2 bar at the rate of 50 m³/min.

Find the power required by a Roofs blower.

(10)

Q.8 A compressor has 150 mm bore and 200mm stroke and the linear clearance is 10

mm. Calculate the theoretical volume of air taken in m³ per stroke when working

between 1 bar and 7 bar. Take n=1.25.

	(10)

 

Q.9 A cylinder contain steam at a pressure of 7 bar and 0.95 dry. The steam is expand

isothermally and reversibly to a pressure of 1.5 bar. Find: 1. the final condition

of steam; 2. the change in enthalpy; 3. the change in internal energy; 4. the

change in entropy; 5. the heat transferred; and 6. the work done per Kg of steam.

 

(10)

Q.10.An ideal engine is imagined to be working on carnots. The working fluid received

heat at the temperature of 590K. and rejects at a temperature of 295K. Find the

theoretical efficiency of the cycle. If the engine working on this cycle absorbs

35 kJ/s from the hot body, calculate the net work done per second

 

Group C (25 Marks)

All Questions are Compulsory.

Q.11 Fill in the blanks ( each question carry 2 marks)

 

1.Otto cycle is also known as _______________________.

2.In an isentropic process__________________________.

3.The maximum delivery pressure in a rotary air compressor is ___________ .

4.The rotio ma/m is called a________________.

5. The brake power is the power available at the _____________________.

 

Q.11 Multiple choice question. (Each question carry 2 marks)

 

1. Which of the following statement is correct as regard to centrifugal compressors

a)         The flow the air is parallel to the axis of the compressor.

b)         The static pressure of the air in the impeller in order to provide centripetal force on the air.

c)         The impeller rotates at high speeds.

d)         The maximum efficiency is higher than multi-stage axial flow compressors.

 

2.The equivalent evaporation is defined as the

e)      ratio of the heat actually used in producing the steam to the heat liberation in the furnace.

f)       amount of water evaporated or steam produced in k.g per kg of fuel burnt.

g)      Amount of water evaporated from and at 100⁰ C into dry and saturated steam.

h)      None of the above.

 

3.When the enthalpy or total heat is h kJ/kg and the enthalpy or sensible heat of

feed water is h_f1 kJ/kg, then the factor of evaporation is given by

4.The process in which heat transferred is equal to the change of enthalpy, is known as

i)     constant pressure process

j)     constant volume process

k)   constant temperature process

l)     constant entropy process

 

5.carnot cycle consists of

m) two constant volume and two reversible adiabatic processes

n)   two isothermal and two reversible adiabatic processes

o)   two constant pressure and two reversible adiabatic processes

p)   one constant volume, one constant pressure and two reversible adiabatic processes

 

Q.11 True or false (each question carry 1 marks).

1.In a boiler various heat losses take place the biggest loss is due to moisture in fuel.

2.If the flow of air through the compressor is perpendicular to its axis, then it

is a centrifugal compressor.

3.The isentropic process on h-s diagram will be a vertical line.

4.The efficiency of carnot cycle may be increased by increasing the highest temperature.

5.A compressor mostly used for supercharging of I.C engines is roots blower.

 

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