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D192044 Pages:2

mechanical efficiency, specific fuel consumption and brake thermal efficiency.
Write short notes on (i) LPG (ii) CNG (iii) Biogas
Define equivalence ratio and explain its significance.
PART C

Answer any four full questions, each carries 10marks.
How catalytic converter helps to reduce emission of an engine?
Explain about Octane and Cetane rating of fuels.
With the help of a pressure — crank angle diagram explain different stages of CI
engine combustion.
Explain detonation in SI engine with the help of auto ignition theory. What are
the factors effecting detonation? Also mention various effects caused by
detonation.
Differentiate between open cycle gas turbine and closed cycle gas turbine.
Derive the expression for optimum pressure ratio for maximum work output.
Air enters an open cycle gas turbine plant at | bar and 30 °C. The pressure ratio
of the plant is 5.6. Compression is carried out in two stages with perfect
intercooling in between. Maximum temperature of the cycle is limited to 700 °C.
Isentropic efficiency of both the compressors are 85% and that of turbine is 90%.
Air flow rate is 1.2 kg/S. Determine the power developed and efficiency of the
plant. C, = 1.02 kJ/kgK and y = 1.41 for both air and gas. Mass of fuel can be
neglected.
With the help of T-S diagrams explain how intercooling, reheating and

regeneration improve the performance of gas turbine cycle.

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