Applied Heat Past Examination Questions

Applied hot up past interrogation Questions 1. An Ammonia refrigerator is to produce 2 tonne of ice per day at -4C from water at 20C. if the temperature range in the compressor is between 25C and -6C, write in code knight source required to derive the compressor. Latent Heat of ice = 80 kcal/kg, and particular(prenominal) erupt of ice= 0. 5 2. A compressor draws 42. 5 m3 of line of credit per bit in the piston chamber, at a public press of 1. 05 kg/cm abs. It is fuddled Polytropically pV1. 3=C to a atmospheric coerce 4. 2 kg/cm2 abs, onward universe delivered to a receiver. Assuming a automatonlike qualification of 80% reason a.Indicated horse actor b. Shaft horse authority, and c. Overall iso thermic capability. 3. A unrivalled stagecoach lust turbine has a advance of 1000rpm and a compressed leaf stigma bounce diameter of 60 cm. The nozzles atomic number 18 habituated at 22 to the plane of gy ration and the specific enthalpy drop is xcl KJ/kg. visua lise a. The relative hurrying of the move at inspiration, and b. The blade niche angle. 4. An locomotive locomotive engine consumes brand of calorific range 44MJ/Kg at a dictate of 45tonne/day. It the indicated thermal qualification is 39% and break thermal creator is 33%. count on a. The indicated power, b. The bracken power, and . The power lost to clangoring. 5. The walkover in a ships p rev upention is maintained at 19C and is changed twice every hour from the outdoors atmosphere which is at 7C. The stripe is 27m by 15m by 3m high. Calculate the kW loading to shake up this line of merchandise taking the saloon to be at atmospherical Pressure = 1. 013 keep out. R for air =0. 287 KJ/kg K. 6. 0. 23kg of air has an initial drive of 1. 7 MN/m2 and a temperature of 200C. it is grow to a hale of 0. 34 MN/m2 agree to the equity pV 1. 35 = Constant. find oneself the work transferred during the expansion. paying back R = 0. 29 KJ/kg K. 7.The equivalent evapor ation of a b oil colorer from and at 100C is 10. 4 kg goerer/kg fuel. The calorific value of the fuel is 29800KJ/kg. find out the efficiency of the boiler. If the boiler produces 15000 kg of move per hour at 24 lug from lean water of 40C and the fuel usance is 1650 kg/h, train the condition of the go produced. 8. A single-cylinder, repeat acting move engine is 250mm practice by 300mm cerebrovascular accident and runs at 3. 5rev/s, traveler is supplied at 1035 KN/m2 and the back public press is 34 KN/m2 and the diagram factor is 0. 81. Determine the indicated power of the engine. a. If cut off is at 0. 5 slash, b. If cut off is at 0. 5 stroke. 9. nisus enters a nozzle with a printing press of 700 KN/m2 and with a temperature of one hundred eightyC. slip by drag is 100 KN/m2. The legal philosophy connecting compel and specific intensity level during the expansion in the nozzle is pV1. 3=Constant. Determine the zippering at plump from the nozzle. Take Cp= 1. 0 06 KJ/kg K and Cv=0. 717 KJ/kg K. 10. A single row, impulse turbine has a retrieve blade speed of 215 m/s. bird of Minerva entry angle is at 30 to the plane of rotation of the blades. The moveer pep pill from the nozzles is 550 m/s. There is 15% going of relative stop number cod to attrition across blades.The infrangible velocity at the exit is along the axis of the turbine. The steam f crushed through the turbine is at the rate of 700 kg/h. Determine a. The inlet and exit angles of the blades, b. The absolute velocity of the steam at exit, c. The power make of the turbine. 11. The high temperature of a Carnot cal give noticear method is four hundredC and the beat has a thermal efficiency of 55%. The intensity level ration of the is other(a)mal care fores is 2 8 1. Determine for the cycle a. The low temperature, b. The volume ration of the adiabatic processes, c. The general thermal efficiency. Take r = 1. 4 12.A diesel engine has a calculus ratio of 141 and an effi ciency ratio of 0. 7 when referred to the air type efficiency. The fuel consumption is 5. 65 kg/h. Take r=1. 4 and calorific value of the fuel oil is 44500 KJ/kg. Determine the indicated power developed. 13. The analysis of a fuel oil is 85. 5% carbon, 11. 9% henry, 1. 6% oxygen and 1% impurities. Calculate the voice of carbon dioxide in the flue blusterolineses, a. When the amount of money of air supplied is the minimum for expel conflagration, and b. When the extra air over the minimum is (i) 25% (ii) 50% iii) 75% 14. In an air compressor the air is compressed to the legality pVn= immutable. The compressor takes in cv m3/min of air at 1. 0 turf out 27C. If the stuff ratio is 5 to 1, shoot for a. The king of coalescence, b. Power absorbed by the compressor. 15. A single acting opposed speculator 6 cylinder two stroke engine have mechanical efficiency of 86% when running at 105 rpm with flirt with strong pressure of 7. 24 bar, produces brake power of 4326 kW. The spile of the top piston with its connecting parts is 25% greater than that of bottom piston and the combine stroke is 2340 mm.If the stroke of piston varies in return as the jackpotes of the reciprocating parts. Calculate (i) The stroke of the top and bottom pistons, (ii) The cylinder diameter. 16. The battalion analysis of a fuel is 86% carbon, 11. 5% enthalpy and 2. 5% oxygen. If for complete combustion 25% excess air is supplied per kg of fuel burnt, wager a. The skunk of flue gases, b. Volume of air at 1. 0 bar and 15C. Take R for air = 0. 287 kJ/kgh. 17. The diameter of an air compressor cylinder is 140 mm, the stroke is 180 mm, and the clearance volume is 77cm. he pressure in the cylinder at the source of the stroke is 1. 0 bar and during auction pitch is constant at 4. 8 bar. fetching the law of compressing as pV1. 25=Constant, calculate the distance moved by the piston during the delivery period and convey this as fraction of the stroke. 18. A turbine name cons ists of H. P. and L. P. stages and is supplied with steam at 15 bar 300C. The steam is expanded in the H. P. and leaves at 2. 5 bar 0. 97 dry. Some of the steam is bled off to the eat up fomenter and remaining passes to L. P. where it is expanded to 0. 15 bar 0. 84 dry.If the same amount of money of work transfer takes place in each unit, calculate the amount of steam bled off expressed as component of the steam supplied. 19. 7. 08 liters of air at a pressure 1. 79 bar and temperature of 333C is expanded according to the law pV 1. 3 = constant and the final examination pressure 1. 206 bar, calculate a. Volume at the remove of expansion, b. organize transfer from the air and, c. The temperature at the closure of expansion. 20. Steam leaves the nozzle and enters the blade single-foot of a single stage impulse turbine at a velocity of 840 m/s and at an angle of 20 to the plane of rotation.The blade velocity is 350 m/s and the exit angle of the blade is 2512. Due to friction th e steam looses 20% of its rotational velocity across the blades, calculate a. The blade inlet angle and, b. The magnitude and the direction of absolute velocity of steam at exit. 21. In a Freon-12 refrigerating fix, Freon leaves the condenser with a specific enthalpy of 50kJ/kgK. The pressure in the evaporator is 1. 826 bars and the refrigerating leaves the evaporator at this pressure at a rate of 0. 4 Kg/s and a temperature of 0C. Calculate a. Dryness fraction of Freon at inlet of the evaporator, b.The refrigerating effect per minute. 22. A glass tobacco pipe of uniform quality is closed at on end and open at the other. It contains air jug by a column of hydrargyrum 42. 7 mm long. When the tube is held vertically with close end at the bottom, the space of the air column is 227. 6mm. Taking 1mm of mercury = 133. 5N/m2 and atmospheric pressure = 101. 5 kN/m2. Calculate the length of the air column if the tube is held vertically with the closed end at the top. 23. A single acti ng gas engine of exercise 190 mm and stroke 380 mm has an indicated power of 13 kW when developing brake power of 9 kW there being 125 explosions per minute.The consumption of gas of calorific value 1. 76 MJ/m3 is 6. 8m3/hour. Calculate the mechanical and indicated thermal efficiencies, and the mean effective pressure. 24. A six cylinder, cardinal stroke, internal combustion engine is required to develop a brake of 176 kW under the side by side(p) conditions Speed 200rev/min, brake m. e. p. 8 bars, stroke/bore ratio 1. 25/1. cut short specific fuel consumption 0. 262 Kg/KWh. Calculate- a. The cylinder dimensions, and b. Fuel consumption kg/h 25. Carbon dioxide leaves a refrigeration condenser with a radical heat of 156kJ/kg.After throttling it passes through the evaporator from and it leaves with a dryness fraction of 0. 98. At the evaporator pressure the liquid heat is 12kJ/kg and the potential heat is 280kJ/kg. If 13. 8 kg of refrigerating circulates per minute, calculate- a. The dryness fraction at the inlet to the evaporator, and b. The heat absorbed in the evaporator in 24 hours. 26. Steam is generated from feed water at a temperature of 93. 3 C as follows In plant A the steam generated is 17. 25 bar dry saturated. In plant B the steam generated is 17. 25 bar 0. 9 dry and, In Plant C the steam generated is 17. 5 bar 82C super heat. Calculate the plowshare change in the consumption utilize plant A as the base. 27. A hydrocarbon fuel cell is completely burned-over with 12. 5 per centum excess air. Calculate the Volume of air used to burn 1Kg of fuel, measured at 1. 01 bars and 18C. Air contains 23 percentage oxygen by issueerpot. Atomic mass family Hydrogen=2, Carbon=12, Oxygen=16. 28. An oil engine has a volumetric capsule ratio of 131. At the initiation of concretion the air in the cylinder is at 1 bar and 15. 6C. Calculate the temperature and pressure at the end of compression if the index of compression is 1. 8. 29. A single acting air compressor running(a) without clearance has a 220mm bore and 200mm stroke. The suck conditions are 1 bar 27C and running speed is 10 rev/sec. if compression is according to the law pV1. 3=Constant and the natural spring pressure is 10 bar. Calculate, a. The mass of air compressed per hour, and b. The discharge temperature. 30. Calculate the final temperatures and final total heat of both(prenominal) (a) and (b). a. irrigate at 65. 6 C having a mass of 45. 36 kg is cooled by placing 4. 536 kg of ice at -8. 9C into the water. b. Water at 65. 6C having a mass of 54. 1 kg is cooled by addition of 22. 68 kg of water at 26. 7C. 31. An impulse steam turbine operates at 50rev/sec. The mean blade tip diameter is 0. 6m. The blade exit angle is 30 and the velocity of the steam relative to the blade at blade exit is 300 m/s. Calculate or determine by any other means the energising susceptibility of steam go forth the blades per kg of steam flow. 32. A perfect gas at 3. 1 bar and 30C i s compressed according to the law pV1. 3=constant until its temperature increases to 215C. Sketch the process on a p-V diagram and calculate a.The pressure at the end of compression. b. The changes in enthalpy and internal energy per kilogram of gas. 33. In an ideal constant volume cycle the temperature at the beginning of compression is 50C. the volumetric compression ratio is 51. If the heat supplied during the bible is 930 KJ/Kg of working changeful, calculate a. The maximum temperature succeed on the cycle, b. Work done during the cycle/kg of working fluid, and c. The thermal efficiency of the cycle. Take ?=1. 4 and Cv= 0. 1717 KJ/Kg K. 34. A fuel has a mass analysis of carbon 87 percent, hydrogen 5. percent and remainder ash. The calorific value of carbon and hydrogen are 34MJ/kg and 145 MJ/kg respectively. Calculate for one kilogram of fuel a. The calorific value, b. The mass of exhaust gas if 35 percent excess air is supplied. When burning fuel, wherefore is excess air use d? Air contains 23 percent oxygen by mass Atomic mass relationships hydrogen=1, oxygen=16, carbon=12. 35. One kilogram of dry saturated steam at 4 bars is contained in a cylinder fitted with a piston. The steam rejects 320 KJ of heat energy at constant pressure is 1. 4 bars. Calculate a.The condition of the steam on completion of change at constant pressure, b. The condition of the steam on completion of cooling at constant volume, and c. The quantity of heat energy spurned during constant volume cooling. 36. A steam turbine which operates at 50rev/s has a mean blade-ring diameter of 1m at a certain(prenominal) stage. The blades are designed for 50 percent reaction and have the exit and inlet angles at 30 and 50 respectively. The turbine is supplied with steam at the ratio of 166. 67kg/s and the stage efficiency is 85 percent. Calculate or determine by any other means a.The power output of the stage, and b. The specific enthalpy drop in the stage. 37. In Ammonia refrigeration pla nt the refrigerating leaves the condenser at 22C as saturated liquid. The evaporator pressure is 2. 077bar and refrigerant leaves the evaporator 0. 98 dry saturated. For a cooling load of 40kW, calculate a. The rate of circulation of the refrigerant (kg/s), b. The effective swept volume of the compressor (m3) if its speed is 1 rev/s. 38. A copper bar of 75mm diameter, 13m long is heated by a direct current rate of flow through the bar. The level electrical insert to the bar is 500W.Assuming the bar is well-insulated and neglecting conduction heat losses at the leads, calculate the wires taken for the temperature of the bar to increase from 5C to 365C. 39. A single stage repeat acting air compressor deals with 18. 2m3 of air per minute measured at conditions of 1. 61325 bar 15C. The condition at the beginning of compression is 0. 965 bar 27C and the discharge pressure is 4. 82 bars. The compression is according to the law pV1. 32=constant. If the mechanical efficiency of the co mpressor is 0. 9 calculate the input power required to drive the compressor. 40.In a steady flow process the working fluid enters and leaves a horizontal system with trifling velocity. The temperature drop from inlet to outlet is 480C and the heat losses from the system are 10KJ/kg of fluid. Determine the power output from the system for a fluid flow of 1. 7kg/s. For fluid Cp=900 J/kgK. 41. A four stroke single cylinder engine working on constant volume cycle, develops 7. 5 KW(Brake) at 60 rev/s, the mechanical efficiency being 0. 8. The pressure at the beginning of compression is 0. 97 bar. The engine has a volumetric compression ratio of 7 and the maximum pressure reached in the cycle is 34 bar.If both compression and expansion is according to the law pV1. 38=constant. Calculate a. The indicated mean effective pressure, and b. The diameter of the cylinder if stroke/bore ratio is 1. 25. 42. A boiler generates steam at 40 bar 400C and supplied to a steam turbine at the rate of 14 kg /s. due to frictional and heat losses the steam at the turbine inlet is at 37 bar 350C. If the steam velocity leaving the boiler is 30 m/s and the change in the kinetic energy of steam is negligible. Calculate a. The diameter of the steam supply pipe, and b. The heat loss from the steam supply pipe.