C D192044 Pages:2

Reg No.:_ Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FOURTH SEMESTER B.TECH DEGREE EXAMINATION(S), DECEMBER 2019
Course Code: ME204
Course Name: THERMAL ENGINEERING

Max. Marks: 100 Duration: 3 Hours
Use of Approved data books are permitted
PARTA
Answer any three full questions, each carries 10marks. Marks
1 Steam at a pressure of 15 bar and 250°C is expanded through a turbine to ௨ (10)

pressure of 4 bar. It is then reheated at constant pressure to 250 °C and finally
expanded to 0.1 bar. Find out the efficiency of this cycle. What will be the
efficiency without reheating? Pump work can be neglected.

2 a) Derive the expression for critical pressure for maximum discharge through 2 (7)

nozzle.
b) Discuss the merits and demerits of water tube boiler over fire tube boiler. (3)
3 What do you meant by governing of steam turbine? Explain different methods of (10)
governing.
4 9) Differentiate between impulse and reaction turbines. (4)
b) Define i) stage efficiency ii) degree of reaction iii) reheat factor. (6)
PART छ
Answer any three full questions, each carries 10marks.
5 89) Compare two stroke and four stroke engines. (4)
b) Prove that efficiency of Ericsson cycle is same as that of Carnot cycle (6)

6 a) Explain the concept of stratified charge engines and mention its advantages over (6)
conventional engines.
b) What do you meant by turbo charging and supercharging? (4)
7 A single cylinder 4 stroke engine was tested and following observations were (10)
noted. Area of indicator diagram = 3 cm’. Length of indicator diagram = 4 cm.
Indicator spring constant is 10 bar/cm. Speed of the engine is 400 rpm. Brake
drum diameter = 120 cm. Dead weight on brake = 380 N. Spring balance reading
is 50 N. Fuel consumption rate is 2.8 kg/hr and calorific value of the fuel is

42000 kJ/kg. Bore is 16 cm and stroke is 20 cm. Find frictional power,

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