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Reg No.:_ Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FOURTH SEMESTER B.TECH DEGREE EXAMINATION(R&S), MAY 2019

Course Code: ME204
Course Name: THERMAL ENGINEERING (ME)
Max. Marks: 100 Duration: 3 Hours
Use of Approved Data Book is Permitted
PARTA
Answer any three full questions, each carries 10marks. Marks
1 An ideal Rankine cycle employs steam as working fluid. Saturated vapor enters the (10)

turbine at 80 bar and saturated liquid exits the condenser at a pressure of 0.08 bar. The
net power output of the cycle is 100 MW. Both turbine and the pump have an isentropic
efficiency of 85%.Determine for the cycle (a) the thermal efficiency, (b) the mass flow
rate of the steam, and (c) the rate of heat transfer into the working fluid as it passes
through the boiler.

2 In a single heater regenerative cycle the steam enters the turbine at 30 bar, 400°C and the (10)
exhaust pressure is 0.1 bar. The feed water heater is a direct contact type which operates at 5
bar. Find 1) the efficiency and specific steam consumption of the cycle, 2) Increase in
efficiency and specific steam consumption as compared to cycle without regeneration. Pump
work may be neglected

3 8) Explain ‘Reheat Factor’. Why is its magnitude always greater than unity? (4)

b) Define the term degree of reaction as applied to a steam turbine. Show that for Parson’s (6)

reaction turbine the degree of reaction is 50%.

4 Explain the working of Babcock-Wilcox boiler with neat sketch and differentiate (10)
between fire tube and water tube boiler.
PART 13
Answer any three full questions, each carries 10marks.
5 98) Compare Otto and Diesel cycle for 1) same compression ratio and heat input, ii) same (4)
maximum pressure and heat input.
b) Explain the supercharging of engine. (6)
6 In an engine working on Diesel cycle, inlet pressure and temperature are 1 bar and 17°C (10)

respectively. Pressure at the end of adiabatic compression is 35 bar. After constant
pressure heat addition, the ratio of expansion is 5. Calculate i) heat addition, 11) heat
rejection and 111) efficiency of the cycle. Assume Y = 1.4, ಛೈ = 1.004 kJ/kg K and Cv=

0.717 kJ/kg
7 2) Sketch the heat balance curves for C I Engine at constant speed and discuss the nature of (4)
curve.
b) Describe Morse test. What are the assumptions made in this test? (6)
8 2) Explain flash point, fire point and calorific value of fuels. (6)
b) Explain the working of a rotary engine with a neat sketch. (4)

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