Powerplant

100問 • 1年前

問題一覧

1. A vacuum gage connected to a tank reads 30 kpa at a location where the barometric reading is 755 mm Hg. Determine the absolute pressure in the tank.

A. 70.6 kpa

2. Determine the pressure exerted on a diver at 30 m below the free surface of the sea. Assume a barometric pressure of 101 kpa and the specific gravity of sea water is 1.03.

A. 404 kpa

3. A compressed spring above the piston exerts a force of 60 N on the piston. If the atmospheric pressure is 95 kpa, determine the pressure inside the cylinder.

A. 108.20 kpa

4. If the absolute temperature is 300°K, what is the equivalent in °R?

D. 540.6°R

5. If the °F scale thrice the °C scale, what are the value 'F and °C?

B. 26 67°C and 80°F

6. Water enters the heater at 30°C and leaves at 150°F, what is the temperature difference in °C?

B. 35.55°C

7. A 5 kg plastic tank that has a volume of 0.2 m3 is filled with liquid water. Assuming the density of water is 1000 kg/m3, determine the weight of the combine system.

C. 205 kg

8. Determine the mass of the air contained in a room whose dimensions are 15 f.t x 20 ft. x 20 ft. Assume the density of the air is 0.0724 lb/ft3.

B. 13.49 slugs

9. The water flows in the channel 200 mm x 300 mm at the rate of 2 m/sec. What is the volume flow in ft3/sec?

D. 4.24 ft3/s

10. Two gaseous streams are mixed together with one stream contains a diameter of 120 mm and specific gravity of 0.86 and speed of 5 m/s and on the other stream is 150 mm and density of 890 kg/m at 2 m/s. Find the mass flow rate at the exit if diameter of exit is 200 mm.

D. 80 kg/s

11. A piston-cylinder device contains 1 kg hydrogen gas. Heat is transferred to the hydrogen as its temperature increases by 10°C. What is the boundary work done during the process?

D. 41 KJ

12. Air enters an adiabatic, steady, flow turbine at 1 Mpa, 527°C through a one square duct with a velocity of 100 m/sec. The air leaves the turbine at 100 kpa 157°C, The mass flow rate of the air in kg/sec is.

D. 435.6

13. A 0.5 kg steel (c =(0.5 KJ/kg°K) rivet cools from 800°K upon being installed in a riveted structure. The entropy changes in KJ/°K of this rivet is.

C. 0.245

14. A 1750 kg car is raised to a height of 18 m by hydraulic hoist. The hydraulic pump has a constant pressure of 800 kpa on its piston. How much volume in m³ should the pump displace to deliver the required work for lifting the car?

A. 0.0386

15. Air at a pressure of 100 kpa has a volume of 0.32 m³. The air is compressed in a reversible adiabatic manner until the temperature is 190°C. The reversible work is-63KJ/kg. Determine the initial temperature.

B. 102.19°C

16. Air at a pressure of 100 kpa has a volume of 0.32 m³. The air is compressed in a reversible adiabatic manner until the temperature is 190°C. The reversible work is-63 KJ/kg. Determine the change of internal energy.

B. 18.68 KJ

17. Three cubic feet of oxygen are compressed in a piston-cylinder in a reversible adiabatic process from a temperature of 300°K and a pressure of 102 kpa until the final volume is one tenth the initial volume. Determine the final temperature.

A. 753.56°K

18. In a reversible adiabatic manner, 17.6 m³/min of air are compressed from 277°k and 101 kpa to 700 kpa. Determine the change of enthalpy.

C. 76.24 kw

19. A Carnot engine receives 130 Btu of heat from a hot reservoir at 600°F and rejects 49 Btu of heat. Calculate the temperature of the cold reservoir.

B.-60.46°F

20. The maximum thermal efficiency possible for a power cycle operating between 1400°F and 280°F is:

C. 60.22%

21. The compression ratio of Brayton cycle is 10. Find the cycle efficiency.

A.60.19%

22. The temperature of four corners of Brayton cycle are 11= 30°C, 12 400°C, t= 1300°C. Find the cycle efficiency.

D. 92.22%

23. A Brayton Cycle has an initial condition of 28°C and maximum temperature at 1450°C. If pressure ratio is 10, find the backward ratio,

B. 0.337

24. A gas turbine on an air standard Brayton Cycle has air entering into the compressor at atmospheric condition and 23°C. The pressure ratio is 10 and the maximum temperature in the cyle is 1000°C. Compute the cycle efficiency per kg of air in percent.

A. 48.21%

25. Air enter the combustion chamber of a gas turbine unit of 500Kpa, 227°C and 40 m/s. The products of combustion leaves the combustor at 59 kpa 1007°C and 150 m/s. Liquid fuel enters with a heating value of 43,00 KJ/kg. The combustor efficiency is 92%. What is the air fuel ratio? Properties of air. At 500°C, h=503.02; At 1280°C, h=1372.25 KJ/kg.

B. 43.40

26. Air enters the compressor of gas turbine at 102 kpa and 320°K with a volume flow rate of 6 m³/s. The compressor pressure ratio is 10 and its isentropic efficiency is 82%. At the inlet to the turbine, the pressure is 100pkpa and the temperature is 1450°K. The turbine has isentropic efficiency of 0.87 and the exit pressure of 102kpa. On the basis of air standard analysis, what is the thermal efficiency of the cycle in percent?

B. 30.18

27. Water enters the cooling tower at 55 °C and leaves at 30 °C while the heat rejected to air is 120 KW. Find the capacity of the pump needed to pump the water.

A.1.15li/s

28. An ideal gas turbine operates with a pressure of 8 and temperature limits of 20°C and 1000°C. The energy. input in the high temperature heat exchanger is 200 KW. Determine the air flow rate in kg/hr.

C. 970

29. The available enthalpy of steam at the exit of boiler in a Rankine cycle is 2900 KJ/kg and enthalpy at the entrance of turbine is 2870 KJ/kg If mass of steam is 3.5 kg/s, find the heat loss between the boiler exit and turbine entrance.

A. 105 kw

31. In an air standard Otto cycle, the clearance volume is 12% of the displacement volume. Find the compression ratio and or thermal efficiency.

D. 0.60

32. A Carnot cycle has a maximum temperature of 220°C and minimum temperature of 20°C. Find the cycle efficiency.

D. 40.57%

33. A steam engine operation between 150°C and 500°C. What is the theoretical maximum thermal efficiency?

D. 45.30%

34. An engine has a bore of 15cm and stroke of 48cm. If the volumetric compression is 2200 cm³, find the engine efficiency.

A. 46.2

35. A Carnot engine requires 40 KJ/sec from the hot source. The engine produces 20 kw of power and the temperature of the sink is 26°C. What is the temperature of the hot source?

D. 325.00°C

36. A Carnot engine receives 130 Btu of heat from a hot reservoir at 600°F and rejects 49 Btu of heat. Calculate the temperature of the cold reservoir.

B. -60.46°F

37. The maximum thermal efficiency possible for a power cycle operating between 1400°F and 280°F is:

C. 60.22%

38. A heat engine is operated between temperature limits of 1380°C and 230°C. Engine supplied with 14,142 KJ per KWH. Find the Carnot cycle efficiency in percent.

D. 69.32

39. An Otto engine has clearance volume of 9%. It produces 350 kw power. What is the amount of heat rejected in KW?

A. 204.45

40. An air standard engine has a compression ratio of 15 and a cut-off ratio of 3. If the intake air pressure and temperature are 100kpa and 28°C. Find the work in KJ per kg.

D. 992.50

41. 62 kg of air with enthalpy of 80 KJ/kg is mixed with another x air until the mixture is 110 kg and 70KJ/kg enthalpy. Find the enthalpy of x air before mixing.

B. 57.10 KJ/kg

42. Air in a conditioned space has 26 °C db and 70% RH,find the wet bulb depression.

D. 17.80 °C

43. A 6 x 5 x 4 m room has a pressure of 101 kpa and temperature of 30 °C (Psat=5kpa). If percent relative humidity is 65% find the mass of vapor (RV=0.423 KJ/kg °K)

C. 3.04 kg

44. A 75% efficient cooling tower has a water entering 45C and wet bulb entering at 25 °C. Find the water exit temperature of water

B. 30 °C

45. The following data were obtained in a small power generating plant Power developed by the steam turbine = 2800 KW. Heat supplied to the steam turbine generator = 3500 KJ/kg. Heat rejected by the steam to the cooling water in the condenser = 2200 KJ/kg. Power required by the feedwater pump to return the condensate to the steam generator=12 KW; Determine the mass flow rate of steam in kg/sec

D. 2.145

46. A simple Rankine cycle produces 40 MW of power, 50 Mvof process heated and rejects 60MW of heat to the surroundings. What is the utilization factor of this cogeneration cycle neglecting the pump work?

B. 60%

47. The ASME evaporation units of a boiler is 24,827,500 KJ/hr. The boiler auxiliaries consumes 2.5 MW.What is the net boiler efficiency if the heat generated by fuel is 32,000,000 KJ/hr

A.49.46%

48. A 150,000 kg of coal supplied to two boiler. One has a capacity of 350 kg/hr and the other boiler has a capacity of 100 kg/hr.How many days to consume the available fuel?

B.14

49. A device used to convert AC current into DC current.

A. Rectifier

51. A classification of gasoline according to its antiknock qualities. The higher the octane number or rating, the greater are the antiknock qualities of the gasoline.

C. Octane Rating

52. The ratio of the length to the width, of a rectangular air grille or duct.

A. Aspect Ratio

53. A steam turbine of 6 MW capacity has a Willan's line equation of m.5.5L+ 3.200 kg/hr. Determine the steam consumption at 73% load, kg/hr.

A.27.290

54. A 18,000 KW geothermal plant has a generator efficiency and turbine efficiency of 90% and 80%. respectively. If the quality after throttling is 16% and each well discharges 220,000 kg/hr. Determine the number of wells are required to produce if the change of enthalpy at entrance and exit of turbine is 500 Ki/kg.

B. 5 wells

55. In a 10 MW geothermal power plant, the mass flow of steam entering the turbine is 20 kg/sec. The quality after throttling is 25% and enthalpy of ground water is 750 KJ/kg Determine the Overall efficiency of the plant..

C. 16.67%

56. Air enters the tower at the rate of 60kg/s. The entrance enthalpy is 86 KJ/kg and exit enthalpy of 53KJ/kg. Find the temperature range of the tower if mass flow rate of water is 30kg/s.

D. 15.76 °C

57. Ground water in a Geothermal Plant has 4 ground water flow of 46 kg/s, if the quality of hot water entering the flash tank is 12%, find the mass of steam entering the turbine.

A. 5.52 kg/s

58. In a 13 MW geothermal power plant, the mass flow of steam entering the turbine is 27 kg/s the quality after throttling is 23% and enthalpy of ground water is 730 KJ/kg. Determine the overall efficiency of the plant

D. 15.38%

59. Air enters the tower at the rate of 60kg/s. The entrance enthalpy is 86 enthalpy of 53KJ/kg. Find the temperature range of the tower if mass flow rate of water KJ/kg and exit is 30kg/s.

D. 15.76 °C

60. A 150 MW turbo-ganorator requires 700,000 kg of steam per hour at rated load and 22,000 kg per hour at zero load Calculate the steam rate in kg/KW-hour at 75% of its rated load

B. 4.72

61. During the dynamometer test of an engine for 1 hr steady load, the engine consumes 40 kg fuel having 43.300 KJ/kg heating value. If the torque developed is 2 5 KN-m during the test at 600 rpm, what is the efficiency of the engine?

B. 32.65%

62. A 4-stroke Gasoline engine has a bore and stroke of 400 mm x 450 mm running at 750 rpm. If the clearance volume is 0 0527 m/s, calculate the engine efficiency

A. 55.82%

63. A 3 MW diesel engine consumes 240 li of 25 API fuel and generates 900 KW-hr Determine the rate of fuel consumed by the engine.

A. 0.2 kg/s

64. A 500 KW diesel engine operates at 101.3 Kpa and 27°C in Manila. If the engine w in Baguio having 93 Kpa and 23°C, what new brake power developed if mechanical is 85%7?

C. 459 KW

65. A 50 Bhp blast furnace engine uses fuel with 10 ft/Bhp-hr. The heating value of the 33,700 KJ/m. Determine the brake thermal efficiency.

A. 28.15%

66. During the dynamometer test of an engine for hr steady load, the engine consumes 40 kg ruel. having 44,000 KJ/kg heating value. If the torque developed is 25 KN-m during the test at 600 rpm, what is the brake thermal efficiency?

Β. 32.13%

67. In a Francis turbine, the pressure gage leading to the turbine casing reads 400 kPa and center of spiral casing is 3m above the tail race. If the velocity of water entering the turbine is 8m/s, what is the net head of the turbine?

D. 47 m

68. From a height of 65m water flows at the rate of 0 85 m/s and driving a water turbine connected to an electric generator revolving at 170 rpm. Calculate the power developed by the turbine in KW if the total resisting torque due to friction is 540 N-m and the velocity of the water leaving the turbine blades is 4 75 m/s.

C. 522.8

69. A pelton type turbine was installed 31m below the head gate of the penstock. The head loss due to friction is 15% of the given elevation. The length of the penstock is 80 m and the coefficient of friction is 0.00093 (Morse). Determine the diameter in meters of the penstock and the power output in KW.

D. 1.686; 13,128.05

70. At a proposed hydroelectric plant site, the average elevation of headwater is 600 m the tailwater elevation is 480m. The average annual water flow is determined to be equal to that volume flowing through a rectangular channel 4m wide and 0.5 m deep and average velocity of 55m/s. Assuming the plant will operate 350 days/year, find the energy kwh that the plant site can developed if the hydraulic turbine that will he used has an efficiency of 78% ani efficiency of 90% Consider a headwork loss of 4% of the available head.

D.73,304,488

71. A running at 400 rpm has a specific speed of 60 rpm and head available is 41 m. If the rating of each turbine installed is 100 kw, how many turbines must be used?

B.4

72. The available flow of water is 25 m/s at 39 m elevation If a hydroelectric plant is to be installed with turbine efficiency of 0 86 and generator efficiency of 92%, what maximum power that the plant could generate?

A. 7567.63 kw

73. A vacuum gage connected to a tank reads 30 kpa at a location where the barometric reading is 755 mm Hg.Determine the absolute pressure in the tank.

A. 70.6 kpa

74. Determine the pressure exerted on a diver at 30 m below the free surface of the sea. Assume a barometric pressure of 101 kpa and the specific gravity of sea water is 1.03.

A. 404 kpa

75. A compressed spring above the piston exerts a force of 60 N on the piston. If the atmospheric pressure is 95 kpa, determine the pressure inside the cylinder.

A. 108.20 kpa

76. If the absolute temperature is 300°K, what is the equivalent in "R?

D. 540.6°R

77. If the °F scale thrice the °C scale, what are the value °F and °C?

B 26 67°C and 80°F

78. Water enters the heater at 30°C and leaves at 150°F, what is the temperature difference in °C?

B. 35.55°C

79. A 5 kg plastic tank that has a volume of 0.2 m3 is filled with liquid water. Assuming the density of water is 1000 kg/m3, determine the weight of the combine system.

C. 205 kg

80. Determine the mass of the air contained in a room whose lb/ft3.dimensions are 15 f.t x 20 ft. x 20 ft. Assume the density of the air is 0.0724

B. 13.49 slugs

81. The water flows in the channel 200 mm x 300 mm at the rate of 2 m/sec. What is the volume flow in ft3/sec?

D. 4.24 ft3/s

82. Two gaseous streams are mixed together with one stream contains a diameter of 120 mm and specific gravity of 0.86 and speed of 5 m/s and on the other stream is 150 mm and density of 890 kg/m at 2 m/s. Find the mass flow rate at the exit if diameter of exit is 200 mm.

D. 80 kg/s

81. The water flows in the channel 200 mm x 300 mm at the rate of 2 m/sec. What is the volume flow in ft3/sec?

D. 4.24 ft3/s

D. 80 kg/s

83. A 150 MW turbo-ganorator requires 700,000 kg of steam per hour at rated load and 22,000 kg per hour at zero load Calculate the steam rate in kg/KW-hour at 75% of its rated load

B. 4.72

84. A 10 MW steam turbine-generator power plant has a full load steam rate of 5 5 kg/KW-hr No Load steam consumption is around 10% of the full load steam consumption Calculate the hourly steam consumption at half load in kg/hr.

A. 30250

85. A 5-MW steam turbine generator power plant has a full-load steam rate of 6 () kg/KW-hr. Assuming no-load consumption at 10% of the full-load. Compute the hourly steam Consumption at GO% load in kg/hr.

B. 19200

86. A boiler uses 2400 kg of coal per hour and air required for combustion is 15 kg per kg coal. If ash loss in 10%, determine the mass of gas entering the chimney

B. 38, 160 kg/hr

87. The gas density of chimney is 0.75 kg/m and air density of 1167 kg/m? If the driving pressure is 0.26 kpa, determine the height of the chimney.

B. 63.56 m

88. The actual velocity of gas entering in a chimney is 5 m/s. The Gas temperature is 25°C and pressure of 97 kpa with a gas constant of 0.287 KJ/kg-k Determine the chimney diameter if mass of gas in 53,000 kg/hr

A. 1,82m

89. A coal fired steam boller uses 3,000 kg of coal par hour. Air required for combustion is 1 Kg/kg of coal at burometric prossure of 98.2 kpa. The flue gas has temperature of 285°C and an average molecular weight of in30. Assuming an ash loss of 11% and allowable gas velocity of 8.6 m/s. find the diameter of chimney

A. 1.794m

90. A waste heat recovery boiler produces 4.8 Mpa (dry saturated) steam from 104°C. The boiler receives energy from 6 kg/s of 954°C dry air. After passing through a was boiler, the temperature of air is had been reduced to 343°C. How much steam in kg/produced? Note At 4.80 Mpa dry saturated h=2796,

C. 1.55

91. A water brake coupled to an engine on test absorbs 90 kw of power Find the mass fresh water through the brake, in kg/min if the temperature increases of the water is 12°C. Assume all the heat generated is carried away by the cooling water

A. 107.50 kg/min

92. A 350 diesel engine has a cooling water that enters at 100°F and leaves at 180°F 4. 19 KJ/kg-K. Find the gallons per minute of water required.

B. 19.61

93. A 310 mm x 460 mm four stroke single acting diesel engine is rated at 170 KW at 28. Fuel consumption at rated load is 0 28 kg/KW-hr with a heating value of 43,912 KJ/h. Calculate brake thermal efficiency.

C. 29.28%

94. A six cylinder, four stroke diesel engine with 76 mm bore x 89 mm stroke was run in laboratory at 1800 rpm, when it was found that the engine torque was 163.5 N-m with cylinders firing but 133 N-m when one cylinder was out. The engine consumed 12.5 per hour with a heating value of 52, 120 KJ/kg and 252 kg of air at 15.6°C per hour the indicated power

C. 34.5 kw

95. A car engine produces and average of 25 KW of power in a period of 10-min during which 1.25 kg of gasoline is consumed. If the heating value of gasoline is 43000 KJ/kg, the efficiency of this engine during this period is

B. 28%

96. A pump delivers 1000 gallons per minute of water at a head of 10 ft. Find the water power needed.

D. 25.82 hp

97. Find the power of motor needed to pump the water at a head of 100m at the rate of 400 Ips if pump efficiency is 70%

C. 560.57 kw

98. A small water jet has a diameter of 75 mm and has a velocity of 15 m/s. What is the horsepower exerted by the jet?

B. 10 hp

99. A pump has a head of 20m at 450 rpm. What is the increase in head developed by the pump is speed increased to 1000 rpm?

D. 78.7

100

100. The power developed by the pump is 30kw. What is the percent decrease in power if speed will decrease by 40%

A. 78.4%

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James Paul Concepcion · 31問 · 1年前

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