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Previous Year Exam Questions for IC Engines and Gas Turbines - ICEG of 2018 - BPUT by Bput Toppers

  • IC Engines and Gas Turbines - ICEG
  • 2018
  • PYQ
  • Biju Patnaik University of Technology BPUT - BPUT
  • Mechanical Engineering
  • B.Tech
  • 776 Views
  • 27 Offline Downloads
  • Uploaded 4 months ago
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Registration No : Total Number of Pages : 02 B.Tech PCME4302 5th Semester Back Examination 2018-19 I.C. ENGINES AND GAS TURBINES BRANCH : MECH Time : 3 Hours Max Marks : 70 Q.CODE : E094 Answer Question No.1 which is compulsory and any FIVE from the rest. The figures in the right hand margin indicate marks. Q1 a) b) c) d) e) f) g) h) i) j) Q2 a) b) Q3 a) b) Q4 a) b) Q5 a) b) Answer the following questions : Draw the valve timing diagram for a high speed gasoline engine. How the variation of specific heat takes place with temperature? What is meant by burning time loss? Explain with the help of p-v diagram? What is the optimum speed for cold starting? What is calorific value? Why cooling should not be excessive? What do you understand by alternative fuels for IC engines? What is triptane rating? What is reserve voltage? What is a flame ionization detector? (2 x 10) A single cylinder four-stroke diesel engine working on dual combustion cycle has a compression ratio of 15:1. The engine draws in air at 1 bar, 27°C and the maximum pressure in the cylinder is limited to 55 bar. If the heat transfer at constant volume is twice that at constant pressure, determine (a) the cut-off ratio, (b) the constant volume pressure ratio, and (c) the thermal efficiency of the cycle. Explain the phenomenon of dissociation. (5) What is the effect of percentage change in the efficiency of Otto Cycle having a compression ratio of 7, if the specific heat at constant volume increases by 1%? What are (a) Exhaust blow - down loss, (b) Rubbing friction loss? (5) Describe with suitable sketches the combustion phenomenon in SI engine, and explain the two phases of combustion. How do the injection timing and the fuel quality affect the engine knock? (5) A simple jet carburetor has to supply 6 kg of air per minute. The air is at a pressure of 1.012 bar and at a temperature of 27°C. Calculate the throat diameter of the choke for air flow velocity of 90 m/s. Take velocity coefficient to be 0.75. Assume the flow to be isentropic and compressible. Describe the types of general injection system. Why the air injection system is not used now-a-days? (5) (5) (5) (5) (5)

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Q6 a) b) Q7 Q8 a) b) c) d) Air enters the compressor of a gas turbine plant operating on Brayton Cycle at 101.325 kPa, 27°C. The pressure ratio in the cycle is 6. Calculate the maximum temperature in the cycle and the cycle efficiency. Assume turbine work to be 2.5 times of compressor work. Describe a typical mist lubrication system used for a two stroke engine. (5) A four stroke gas engine has cylinder diameter of 27 cm and piston stroke of 45 cm. The effective diameter of the brake is 1.62 m. The observations made in a rest of the engine were as follows : Duration of test : 38 minute 30 second Total number of revolutions : 8080 Total number of explosions : 3230 Net load on the brake : 903 N Mean effective pressure : 5.64 bar Gas used : 7.7 m3 Pressure of gas at meter : 135 mm of water above the atm. pressure Temperature of the gas : 27°C Height of the Barometer : 75 mm of Hg Calorific value of gas : 18420 kJ/m3 at NTP Mass of jacket cooling water : 183 kg Rise in temperature of the cooling water : 47°C Draw up a heat balance sheet and calculate the indicated and brake thermal efficiency. (10) Write short answer on any TWO : Thermo – syphon cooling and evaporative cooling Willian’s line method Wankel engine ASTM curve (5) (5 x 2)

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