JNTU
JNTU B.Tech III IC ENGINES AND GAS TURBINES Previous Question Paper (February - 2023 - R16)
Note: 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 materials for different parts of an IC Engines.
Answer
Common materials used for IC engine components are as follows:
- Cylinder Block: Cast iron or aluminum alloy.
- Piston: Aluminum alloy (for light weight and thermal conductivity) or cast iron.
- Crankshaft: Forged steel or nodular cast iron.
- Connecting Rod: Forged steel or aluminum alloy.
- Valves: Heat-resistant alloy steels (e.g., silicon-chromium steel).
What is Octane number?
Answer
The Octane number is a numerical rating that indicates the anti-knock quality of a spark-ignition (SI) engine fuel. It represents the fuel's resistance to auto-ignition or 'knocking' during the combustion process.
It is defined as the percentage by volume of iso-octane in a mixture of iso-octane and n-heptane that produces the same knocking intensity as the fuel being tested under standardized operating conditions. Iso-octane is assigned an octane number of 100 due to its high resistance to knocking, while n-heptane is assigned a value of 0 due to its high tendency to knock.
Write the classification of Fuel Injection System.
Answer
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Define Detonation.
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Define specific fuel consumption.
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Why Morse test is not suitable for single cylinder engine?
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State the merits and demerits of gas turbines over IC Engines.
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Draw the T-S Diagram of closed cycle gas turbine.
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What are the basic components used in turbojet engine?
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Write the advantages and disadvantages of turboprop engines.
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Part B
Write the difference between 2-stroke and 4-stroke engines.
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List out the properties of S. I and C. I Engine fuels.
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Explain the working of a 4-stroke diesel Engine with suitable diagrams.
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Explain in detail the working of simple carburetor.
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Explain the working of any one type of fuel feed pump with the help of neat sketch.
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Explain in detail gasoline direct injection system with neat sketch.
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A Trial was conducted on a single cylinder oil engine having a cylinder diameter of 30 cm and stroke 45 cm. the engine is working on the four stroke cycle and the following observations were made: Duration of trial= 50 mins, total fuel used=6 litres, calorific value=42MJ/kg, total number of revolution=12624, Gross imep=7.25 bar, pumping imep=0.35 bar, net load on the brake= 150kg, diameter of the brake wheel drum= 1.78m, diameter of the rope= 4 cm, cooling water circulated=500 litres, cooling water temperature rise= 45oc, specific heat of water= 4.18kj/kg K, specific gravity of oil= 0.8. Calculate the mechanical efficiency and also the unaccounted losses.
Answer
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Explain the working of an open cycle gas turbine with Reheat with neat sketch.
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What is the effect of intercooling and regeneration on the work output and efficiency of gas turbine? Explain.
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Explain different types of combustion chambers used in jet propulsions.
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Explain the difference between propeller jet, turbo jet and turbo prop.
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A Turbo jet has a speed of 700 km/h while flying at an altitude of 10000m. The propulsive efficiency of the jet is 50% and overall efficiency of the turbine plant is 17%. The density of air at 10000 m altitude is 0.170 kg/m3. The drag on the plant is 6150 N. the calorific value of the fuel is 45000kj/kg. Calculate a) absolute velocity of the jet b) volume of air compressed per minute c) diameter of the jet d) power output of the unit in KW e) Air-fuel ratio?
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