JNTU
JNTU B.Tech III IC ENGINES AND GAS TURBINES Previous Question Paper (March - 2024 - R16)
i) Question paper consists of Part A, Part B.
ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions.
iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Name the parts of an I C Engine.
Answer
The essential parts of an IC engine include the cylinder block, cylinder head, piston, piston rings, connecting rod, crankshaft, valves (intake and exhaust), camshaft, spark plug (for petrol engines) or fuel injector (for diesel engines), and the crankcase.
What is Cetane number?
Answer
Cetane number is a measure of the ignition quality of diesel fuel. It represents the ignition delay period; a higher cetane number indicates a shorter ignition delay, meaning the fuel ignites more readily when injected into the combustion chamber, leading to smoother engine operation.
State the function of a carburetor in a petrol engine.
Answer
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Define Knocking.
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Define Brake thermal efficiency.
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Explain various methods to find friction power of an IC engine.
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Draw the P-V Diagram of open cycle gas turbine.
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What is the importance of Reheating?
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Write a short on gas turbine emissions.
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Explain the principle of jet propulsion.
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Part B
Write the difference between SI and CI Engines.
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Explain the working principle of 2-stroke Petrol Engines.
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Explain the working of a 4-stroke Petrol Engine with suitable diagrams.
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With the help of P-θ diagram, explain various stages of combustion in CI engine.
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Compare the phenomenon of Knocking in SI and CI Engine with suitable diagrams.
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Explain in detail Common Rail Direct Injection (CRDI) system with neat sketch.
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An Six cylinder, four stroke engine of 9 cm and 8 cm stroke with a compression ratio of 7 is tested at 4500 rpm on a dynamometer which has 54 cm arm. During a 10 minutes test the dynamometer scale beam reading was 42 kg and the engine consumed 4.4 kg of gasoline having a calorific value of 44000 kj/kg. Air 27 0c and 1 bar was supplied to the carburetor at the rate of 6 kg/min. find a) the brake power b) the brake mean effective pressure c) the brake specific fuel consumption d) the brake specific air consumption e) the brake thermal efficiency f) the volumetric efficiency g) the air-fuel ratio?
Answer
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A gas turbine unit has a pressure ratio of 6:1 and maximum cycle temperature of 610 0C. The isentropic efficiencies of the compressor and turbine are 0.80 and 0.82 respectively. Calculate the power output in kilowatts of an electric generator geared to the turbine when the air enters the compressor at 150C at the rate of 16 kg/s. take cp=1.005kj/kgK and γ=1.4 for the compression process, and take cp=1.11 kj/kgK and γ=1.333 for the expansion process?
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Explain in detail the effect of operating variables on thermal efficiency of a gas turbine.
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Write the merits and demerits of closed cycle gas turbine over open cycle gas turbine.
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Explain the working of turbo jet cycle in detail with suitable diagrams.
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A Turbo jet engine inducts 51 kg of air per second and propels an aircraft with an uniform flight speed of 912km/h. the isentropic enthalpy change for the nozzle is 200 kj/kg and its velocity coefficient is 0.96. The fuel-air ratio is 0.019, the combustion efficiency is 0.96 and lower heating value of the fuel is 42 MJ/KG. Calculate a) the thermal efficiency of the engine b) the fuel flow rate in kg/h and TSFC c) the propulsive power in KW d) the thrust power and e) the propulsive efficiency?
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