GITAM University 2006 B.E Mechanical Engineering Applied Thermodynamics - II - Question Paper

College of Engineering
Gandhi Institute of Technology and Management, Visakhapatnam
(Affiliated to Andhra University)

B.E. (Mechanical Engineering)
Third Year 1st Semester exams 2005-2006
(Autonomous Stream)









ME 313 Applied Thermodynamics - II






Time: three Hours Max. Marks: 60

1. Answer ques. No. one ( Part – A) and any 4 of the remaining 7 (Part – B)
2. All parts of a ques. must be answered in 1 place, otherwise they will not be valued.
3. Figures in the right hand margin indicate marks allotted.

PART – A

1. Answer the subsequent (10x2=20)
a) What is meant by ‘valve timing diagram’? What useful info does it gives?
b) What are the different kinds of cooling systems used in IC engine?
c) Indicate the factors that influence flame velocity.
d) What is ignition timing? How can it effect combustion?
e) What is meant by calorific value of a fuel? Differentiate ranging from H.C.V. abnd L.C.V.
f) Why staging is done in reciprocating compressor?
g) What is a rotary compressor? How are rotary compressors classified?
h) What is the difference ranging from turbojet and turboprop engine
i) What is adiabatic saturation?

j) Define: i) Specific humidity ii) Dew point temperature.

PART – B

ans any 4 of the subsequent. If you attempt more than 4 questions, only the 1st 4 in order will be valued.

2. a) Explain the different events that take place in an internal combustion engine. (5)
b) An engine working on the Otto cycle is supplied with air at 0.1 Mpa, 350 C. The compression ratio is 8. Heat supplied is 2100 kJ/kg. compute the maximum pressure and temperature of the cycle, the cycle efficiency, and the mean effective pressure. For air, Cp=1.005J/kgK, Cv=0.718J/kgK and R=0.287 kJ/kgK. (5)
3. A 4 cylinder, 4 stroke oil engine 10 cm in diameter and 15 cm in stroke develops a torque of 185 Nm at 2000 rpm. The oil consumption is 14.5 Lit/hr. The specific gracity of the oil is 0.82 and calorific value of oil is 42 MJ/kg. If the imep is obtained to be 6.7 bar obtain i) mechanical efficiency ii) brake thermal efficiency iii) brake mean effective pressure and iv) specific fuel consumption in litres on brake power basis. (10)
4. a) Explain the phenomenon of detonation in spark Ignition engine. elaborate the main factors which effect detonation? (3)
b) Sketch the combustion chambers of SI engines. (3)
c) Find the higher and lower calorific values and the minimum air needed for complete combustion of one kg of low grade fuel with C = 42%, H2 = 8% and the remaining incombustible material. (4)
5. a) Derive an expression for the shaft work of a reciprocating compressor assuming zero clearance quantity. (4) b) Discuss the reasons for the use of multi – stage compressors. (3)
c) What are the various applications of centrifugal compressors and their limitations? (3)
6. a) Draw line diagram of an open kind gas turbine power plant and indicate the function of every component. (5)
b) In a gas turbine plant, the air is compressed in a single stage compressor from one bar to nine bar and from an initial temperature of 300 K. The identical air is then heated to a temperature of 800 K and then expanded in the 2nd turbine. obtain the maximum power that can be found from the installation, if the mass of air circulated per 2nd is two kg. Take Cp = 1.005 kJ/kg C for air. (5)
7. a) Explain the working of solid and liquid propellant rocket engines. (5)
b) The effective jet exit velocity from a rocket is 2500 m/s. The forward flight velocity is 1250 m/s and the propellant consumption is 60 kg/s. compute
i) thrust ii) thrust horsepower and iii) propulsive efficiency. (5)
8. a) Draw a line diagram of vapor compression refrigeration system and discuss its working. (4)
b) What are the basic requirements of a good refrigerant? (2)
c) In an open cycle air refrigeration system, air is drawn from a cold chamber at –5 C and I bar and compressed to six bar. The air is then cooled to 20 C and then expanded to one bar. The compression and expansion follow PV1.35 = C. To produce 10 tons of refrigeration, obtain the mass flow rate of air to be circulated. Also obtain the COP, power needed to compress and rate of heat rejection in the heat exchanger. (4)

Earning:   Approval pending.