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18MEC107T APPLI ED THERMALENGI NEERI NG CT-2 IMPARTANT QUESTION BANK Part-A (Answer all the questions) 1. The process of burning fuels in presence of oxygen is called _____. (CLO-2) (L1) a) Induction b) Ignition c) Condensation d) Combustion 2. The minimum temperature at which a substance begins to burn is ___. (CLO-2) (L2) a) Fire point temperature b) Auto ignition c) Ignition temperature d) Flash point temperature 3. Which calorimeter is used to find calorific values of gaseous fuels? (CLO-2) (L2) a) Bomb calorimeter b) Isothermal titration calorimeter c) Adiabatic calorimeter d) Junker calorimeter 4. Which of the following fuel has the highest calorific value? (CLO-2) (L1) a) Lignite b) Bituminous coal c) Peat d) Anthracite 5. The Gas having lower calorific value is _________. (CLO-2) (L1) a) Producer gas b) Coal gas c) Coke-Oven Gas d) Blast furnace gas 6. The mass of carbon per kg of flue gas is given by _______. (CLO-2) (L2) a) 11/3 CO2 + 3/7 CO b) 3/11 CO2 + 3/7 CO c) 3/7 CO2 + 11/3 CO d) 7/3 CO2 + 11/3 CO 7. Which is the common method to relate higher calorific value to lower calorific value? (CLO-2) (L2) a) HCV = LCV + HV (nH2O, out / nfuel, in) b) LCV = HCV + HV (nH2O, out / nfuel, in) c) HCV = LCV + HV (nfuel, in/ nH2O, out) d) LCV = HCV + HV (nfuel, in/ nH2O, out) 8. In the Orsat apparatus KOH solution is used to absorb ______ . (CLO-2) (L2) a) CO b) CO2 c) O2 d) SO2 9. In presence of which gas is the fuel burnt to generate energy in form of heat? (CLO-2) (L1) a) Oxygen b) Hydrogen c) Methane d) Nitrogen 10. The amount of heat liberated by complete combustion of unit quantity of fuel is known as _____. (CLO-2) (L2) a) Agitation b) Combustion c) Calorific value d) Thermogenesis 11. Which calorimeter is used to find calorific values of solid and liquid fuels? (CLO-2) (L1) a) Boy’s calorimeter b) Bomb calorimeter c) Junker’s calorimeter d) Calvet-type calorimeter 12. Which of the following fuel has the highest calorific value? (CLO-2) (L1) a) Producer gas b) Coal gas c) Mond gas d) Blast furnace gas 13. 1kg of carbon requires ____ of oxygen and produces 7/3 kg of CO. (CLO-2) (L3) a) 7/3 b) 4/3 c) 8/3 d) 11/3 14. A good fuel has __________. (CLO-2) (L2) a) low ignition point and high calorific value b) low ignition point and low calorific value c)hi ghi gni t i onpoi ntandhi ghcal or i ficv al ued)hi ghi gni t i onpoi ntandl ow cal or i ficv al ue

15. 1kg of CO requires 4/7 kg of oxygen and produces ______. (CLO-2) (L2) a) 11/3 kg of CO2 b) 7/3 kg of CO c) 11/7 kg of CO2 d) 8/3 kg of CO 16. C + O2 => _____ a) CO b) CO2 c) CO3 d) 2CO 17. Which fuel is called secondary stage in the formation of coal? (CLO-2) (L2) a) Lignite b) Bituminous coal c) Peat d) Anthracite 18. Which fuel is commonly available in both caking and Non-caking forms? (CLO-2) (L1) a) Lignite b) Bituminous coal c) Peat d) Anthracite 19. Which fuel is the final stage in formation of coal? (CLO-2) (L2) a) Bituminous coal b) Anthracite coal) c Peat d) Lignite 20. Which form of fuel is used as domestic form of fuel? (CLO-2) (L1) a) Wood b) Bituminous Coal c) Dung cake d) Anthracite coal 21. In presence of which gas is the fuel burnt to generate energy in form of heat? (CLO-2) (L2) a) Oxygen b) Hydrogen c) Methane d) Nitrogen 22. Which are the main constituents of fuel from given options? (CLO-2) (L1) a) Carbon and Nitrogen b) Oxygen and Hydrogen c) Carbon and Hydrogen d) Helium and Oxygen 23. What is the significance of calorific value? (CLO-2) (L2) a) Helps in deciding which fuel is good b) Helps in locating fuel c) Helps in deciding ignition temperature d) Helps in deciding fire point 24. Which gas has the highest calorific value among given option? (CLO-2) (L1) a) Oxygen b) Helium c) Hydrogen d) Nitrogen 25. The fuel mostly used in Boilers is ______________. (CLO-2) (L2) a) Peat b) Brown Coal c) caking bituminous coal d) non- caking bituminous coal 26. If one cylinder of a diesel engine receives more fuel than the others, then for that cylinder the _______ . (CLO-2) (L1) (a) exhaust will be smoky (b) scavenging occurs (c) exhaust temperature will be high (d) engine starts overheating 27. The output of a diesel engine can be increased without increasing the engine revolution or size in following way? (CLO-2) (L2) (a) feeding more fuel (b) supercharging (c) heating incoming air (d) scavenging 28. The theoretically correct air fuel ratio for petrol engine is of the order of (CLO-2) (L2) (a) 6 : 1 (b) 9 : 1 (c) 12 : 1 (d) 15 : 1 29. Air fuel ratio for idling speed of a petrol engine is approximately (CLO-2) (L2) (a) 1 : 1 (b) 5 : 1 (c) 10:1 (d) 15 : 1 30. Combustion in compression ignition engines is ________ . (CLO-2) (L1) (a) homogeneous (b) heterogeneous (c) turbulent (d) laminar 31. The fuel in diesel engine is normally injected at pressure of (CLO-2) (L1) (a) 5-10 kg/cm2 (b) 20-25 kg/cm2 (c) 60-80 kg/cm2 (d) 90-130 kg/cm2 32. The specific fuel consumption per BHP hour for diesel engine is approximately (CLO-2) (L1) (a) 0.15 kg (b) 0.2 kg (c) 0.25 kg (d) 0.3 kg 33. The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft _______________. (CLO-3) (L1)

(a) 1/2 (b) 1 (c) 2 (d) 4 34. Combustion in compression ignition engines is ________ . (CLO-3) (L2) (a) homogeneous (b) heterogeneous (c) turbulent (d) laminar 35. In a 4-cylinder petrol engine the standard firing order is ____. (CLO-3) (L2) (a) 1-2-3-4 (b) 1-4-3-2 (c) 1-3-2-4 (d) 1-3-4-2 36. The frictional power (F.P.) is given by_____ . (CLO-3) (L3) a) F.P. = B.P-I.P. b) F.P. = I.P-B.P c) F.P = B.P./I.P. d) F.P. = I.P./B.P. 37. Mechanical efficiency of an IC engine indicates percentage of ______. (CLO-3) (L2) a) BP converted into IP b) heat converted into work c) IP converted into BP d) heat lost into exhaust 38. Mechanical efficiency is ratio between ___________ and ___________. (CLO-2) (L1) a) Indicated Power, Mean effective Pressure b) Indicated Power, Brake Power c) Brake Power, Indicated Power d) Brake Power, Mean effective pressure 39. Iso-octane (C₈H₁₈) has octane number of (CLO-2) (L1) a) 50 b) 75 c) 100 d) 120 40. Compression ratio of diesel engine may have a range___. (CLO-3) (L1) a) 8 to 10 b) 10 to 15 (C) 16 to 20 d) 20 to 40 41. The ignition quality of diesel oil is expressed by____ . (CLO-3) (L1) a) Octane number b) Cetane number c) Calorific value d) density 42. The ratio of the indicated thermal efficiency to the air standard efficiency is known as _____ . (CLO-3) (L2) a) Mechanical efficiency b) Overall efficiency c) Volumetric efficiency d) Relative efficiency 43 . The air-fuel ratio of the petrol engine is controlled by _____. (CLO-3) (L1) (a) fuel pump (b) governor (c) injector (d) carburetor 44. A stoichiometric air-fuel ratio is _________ . (CLO-3) (L1) (a) Chemically correct mixture (b) lean mixture (c) rich mixture for idling (d) the ratio used at full rated parameters. 45. The inlet value of a 4 stroke cycle I.C engine remains open for nearly___ . (CLO-3) (L2) (a) 180° (b) 125° (c) 235° (d) 200° 46. Thermal efficiency of an IC engine indicates percentage of _____ . (CLO-3) (L2) a) BP converted into IP b) heat converted into work c)I Pconver t edi nt oBPd)heatl osti nt oexhaust 47. The power actually developed by the engine cylinder of an IC engine is known as _______. (CLO-3) (L1) a) Brake power b) Indicated power c) Actual power d) Friction power 48. Compression ratio of petrol engines is in the range of ______ . (CLO-3) (L2) a) 2 to 3 (B) 7 to l0 (C) 10 to 20 (D) 20 to 40 49. The ignition quality of petrol oil is expressed by _____ . (CLO-3) (L1) a) Octane number b) Cetane number c) Calorific value d) density 50. Compression ratio of diesel engine may have a range ______. (CLO-3) (L1) a) 8 to 10 b) 10 to 15 (C) 16 to 20 d) 20 to 40

PART-B (6x4=24) (Answer any 6 from 8 Questions) 1. How fuels are classified. Give one example for each. (CLO-2) (L2) 2. What is octane number and cetane number? (CLO-2) (L1) 3. What are gaseous fuels & give examples with their merits & demerits? (CLO-2) (L1) 4. Define calorific value. Explain higher & lower calorific value. (CLO-2) (L2) 5. Explain adiabatic flame temperature. (CLO-2) (L1) 6. Calculate the HCV of a coal specimen from the following date: mass of coal burnt is 1g, quantity of water in calorimeter is 2.5 kg, increasing temperature of water 2.6°C, and water equivalent of apparatus is 390g. If the fuel used contains 6% of H2, find its LCV. (CLO-2) (L4) 7. Write the importance of flue gas analysis. (CLO-2) (L1) 8. Write a brief note on CNG and mention its advantages and disadvantages. (CLO-2) (L1) 9. Explain the physical and chemical properties of gaseous fuel. (CLO-2) (L2) 10. What is the significance of treatment of fuels? (CLO-2) (L1) 11. The following data refers to a calorific value test of a fuel by means of a gas calorimeter. Volume of gas used=0.7m3, mass of water heated=25kg, rise in temperature of water=14°C, mass of steam condensed=0.028kg. Find HCV and LCV per m3 at STP. Take the heated liberated in condensing water vapour and cooling the condensate as 2475kJ/kg. (CLO-2) (L4) 12. Find the brake mean effective pressure of a four cylinder, 4 stroke diesel engine having a bore of 100mm and 120 mm stroke which develops a power of 42 kW at 1200 rpm. (CLO-3) (L4) 13. Compare relative advantages and disadvantages of 4-stroke and 2 stroke engine. (CLO-3) (L2) 14. A 4 cylinder 4 stroke petrol engine develops 14.7 kW at 1000rpm. The mean effective pressure is 5.5 bar. Calculate the bore and stroke of the engine, if the length of the stroke is 1.5 times that of stroke. (CLO-3) (L4) 15. Distinguish between petrol engine and diesel engine. (CLO-3) (L2) 16. Draw the ideal and actual p-V diagram for Otto engine. (CLO-3) (L2) 17. Describe how Indicated power of a multi cylinder engine is measured. (CLO-3)(L2) 18. Explain Rope Brake dynamometer with neat sketch. (CLO-3) (L2) 19. Explain the measurement of in-cylinder pressure using Piezoresistive pressure sensors. (CLO-3) (L3) 20. A diesel engine has a brake thermal efficiency of 30 %. If the calorific value of fuel is 42000KJ/Kg. Find its Brake specific fuel consumption. (CLO-3) (L4) 21. Explain the following engine parameters (i) Brake specific fuel consumption (ii) Volumetric efficiency. (CLO-3) (L2) 22. Draw the Heat balance sheet of IC engines. (CLO-3) (L3) 23. What do you mean by performance of I.C engine? (CLO-3) (L2)

PART-C (3x12=16) 1. Determine the higher calorific value of solid fuel using any one of the calorimeter with neat diagram. (CLO-2) (L3) 2. Determine the higher calorific value of gaseous fuel using any one of the calorimeter with neat diagram. (CLO-2) (L2) 3. A steam boiler uses pulverized coal in the furnace. The ultimate analysis of coal by mass as received is C 78%, O2 6% S 1%, H2 3%, ash 10% and moisture 5%. Excess air supplied is 30%. Calculate the mass of air to be supplied and mass of gaseous product formed per kg of coal burnt. (CLO-2) (L4) 4. A sample of coal was found to contain the following elements, C-81%, H-4%, O-2%, N-1% and the remaining ash. Estimate the quantity of minimum air required for the complete combustion of 3kg of coal sample. 5. A natural gas has the following molar analysis: CH4, 80.62%; C2H6, 5.41%; C3H8, 1.87%; C4H10, 1.60%; N2, 10.50%. The gas is burned with dry air, giving products having a molar analysis on a dry basis: CO2, 7.8%; CO, 0.2%; O2, 7%; N2, 85%. (a) Determine the air–fuel ratio on a molar basis. (b) Determine the percent of theoretical air. (CLO-2) (L4) 6. Coal has the following ultimate analysis on a dry basis, percent by mass: Sulfur 0.6, Hydrogen 5.7 ,Carbon 79.2, Oxygen 10.0, Nitrogen 1.5, Ash 3.0 This coal is to be burned with 30% excess air. Calculate the air–fuel ratio on a mass basis. (CLO-2) (L4) 7. Calculate the Gross and Net calorific values of a coal having the following compositions, C = 63 %, H2 = 19 %, O2 = 03 %, S = 13 % and ash=2. Latent heat of steam is = 587 cal/gm. (CLO-2) (L4) 8. Sketch and explain the use of Orsat apparatus used in determining the percentage of exhaust gases. (CLO-2) (L3) 9. During a boiler trial, the flue gas analysis by volume was reported as CO2 13%, CO 0.3%, O2 6% and N2 80.7%. the coal analysis by mass reported as C 62.4%, H2 4.2%, O2 4.5%, moisture 15% and ash 13.9%. Calculate 1) minimum air required to burn 1kf of coal, 2) Mass of air actually supplied per kg of coal. 3) The amount of excess air supplied per kg of coal burnt. (CLO-2) (L4) 10 . Explain the method of measuring brake power by rope brake dynamometer and frictional power by Willan’s line method. (CLO-3) (L3) 11. Explain the working of four stroke diesel engine with neat sketch along with valve timing diagram. (CLO-3) (L2) 12. The following observations were recorded in a test of one hour duration on single-cylinder oil engine working on four-stroke cycle, Bore = 300 mm, stroke=450 mm, Fuel =8.8 kg, CV=41800 kJ/kg, rpm=200 rpm, m.e.p=5.8 bar, Brake friction load = 1860 N, quantity of cooling water: 650 kg, Temp rise = 22oC, diameter of the brake wheel =1.22m. Calculate (i) ɳmech (ii) ɳB.Th (iil) Draw heat balance sheet. (CLO-3) (L4) 13. Explain the characteristics curves for performance of a diesel engine for the following: (i) Constant speed engine (ii) Variable speed engine (CLO-3) (L3) 14. Explain the working of two stroke engine with neat sketch along with port timing diagram . (CLO3) (L2)

15. Explain any one type of measurement of air consumption in IC engine. (CLO-3) (L3) 16. Explain the working of two petrol stroke engine with neat sketch along with port timing diagram. (CLO-3) (L2) 17. Explain the working of four stroke petrol engine with neat sketch along with valve timing diagram. (CLO-3) (L2) 18. Following data relates to 4 cylinder, single stroke petrol engine. A/F ratio by weight 16:1. Calorific value of the fuel= 45200 Kj/kg, mechanical efficiency=82%.Air standard efficiency=52%,relative efficiency=70%,volumetric efficiency=78%, L/D=1.25, suction condition=1 bar, 250C. Speed=2400 rpm and power at brakes=72kw. Calculate 1. Compression ratio 2. Indicated Thermal Efficiency 3. Brake specific fuel consumption 4. Bore and Stroke. (CLO-2) (L4) 19. Explain the working of two stroke diesel engine with neat sketch along with port timing diagram. (CLO-3) (L2) 20. Explain the working of four stroke diesel engine with neat sketch along with valve timing diagram. (CLO-3) (L2) 21. The following results were obtained in a test on a gas engine. Gas used = 0.16 m3/min at NTP, calorific value of gas at NTP : 14MJ/m3; Density of gas at NTP = 0.65 kg/m 3; Air used : 1.5 kg/min; specific heat of exhaust gas 1kJ/kgK Temperature of exhaust gas : 400°C; Room Temperature : 20°C; cooling water per minute: 6 kg; Rise in temperature of cooling water: 30°C Brake power: 10.5 kW. Draw a heat balance sheet for the test on per hour basis in KJ. (CLO-3) (L4) 22. A single cylinder CI engine with a brake thermal efficiency of 30% uses diesel having a calorific value of 42000kJ/kg. If its mechanical efficiency is 80%, calculate (i) Brake specific fuel consumption (ii) Indicated specific fuel consumption (iii) Indicated thermal efficiency. (CLO-3) (L4)...