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PIPE Review materials
Mechanics Of Fluids (MECH 40A)
University of Cebu
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POWER AND INDUSTRIAL PLANT
ENGINEERING-ALCORCON
THERMODYNAMICS
- What is the pressure 8,000 ft. (2000m) below the surface of the ocean? Neglect the compressibility factor, SI units. Answer: B A. 21. B. 20. C. 21. D. 22.
- What temperature at which water freezes using the Kelvin scale? Answer: B A. 373 B. 273 C. 278 D. 406
- The SI units of temperature is: Answer: B A. oF B. oK C. BTU D. oR
- The pressure reading of 35 psi in kpa is: Answer: A A. 342. B. 724. C. 273. D. 427.
- 1 torr is equivalent to pressure Answer: D A. 1 atm B. 2mm Hg C. 14. D. 1/760 atm
- What is the standard temperature in the US? Answer: A A. Fahrenheit B. Rankine C. Celsius D. Kelvin
- Given steam pressure of 900 lb/ft 2 , temperature of 300oF, specific volume of 5 ft 3 /lb. If the specific enthalpy is 9500 ft-lb/lb, what is the internal energy per lb of the system? Answer: D A. 4400 B. 3900 C. 3600 D. 4280
- The barometer reads 29 inches ( mm) of mercury. What is the absolute pressure if a vaccum gage reads 9 psi (66 kpa) in SI? Answer: A A. 32 kpa B. 33 kpa C. 31 kpa D. 31 kpa
- A fluid with a vapor pressure of 0 Pa and a specific gravity of 12 is used in a barometer. If the fluid column height is 1m, what is the atmospheric pressure? Answer: D A. 150 kpa B. 115 kpa C. 144 kpa D. 117 kpa
- What is the atmospheric pressure on a planet if the pressure is 100 kpa and the gage pressure is 10 kpa? Answer: D A. 10 kpa B. 100 kpa C. 80 kpa D. 90 kpa
- A column of water 200 cm high will give a pressure equivalent to: Answer: D A. 9810 dyne/cm 2 B. 0 atm C. 0 bar D. 19,620 N/m 2
- What is the equivalent oR of 400ok? Answer: A A. 720 B. 851 C. 670 D. 344
- If the temperature inside the furnaces is 700oK, what is the corresponding reading in oF? Answer: D A. 700. B. 750. C. 860. D. 800.
- If the oF scale is twice the oC scale, what will be the corresponding reading in each scale? Answer: B A. 22 oC and 44 oF B. 160 oC and 320 oF C. 40 oC and 80 oF D. 100 oC and 200 oF
- Water enters the condenser at 25oC and leaves at 40oC. What temperature difference in oF? Answer: C A. 25 B. 26 C. 27 D. 28
- Water enters the heater with 28oC and leaves at 75oC. What is the temperature change in oF? Answer: C A. 74. B. 38. C. 84. D. 57.
. 17. The specific gravity of mercury relative to water is 13. What is the specific weight of mercury? The specific weight of water is 62 lb per cubic foot. Answer: B A. 102 KN/m 3 B. 132 KN/m 3 C. 150 KN/m 3 D. 82 KN/m 3 18. An iron block weighs 5 N and has a volume of 200 cm 3 What is the density of the block? Answer: C A. 988 kg/m 3 B. 1255 kg/m 3 C. 2550 kg/m 3 D. 800 kg/m 3 19. The suction pressure of a pump reads 540 mmHg vaccum. What is the absolute pressure in kpa? Answer: D A. 40 B. 3. C. 60 D. 29. 20. A boiler installed where the atmospheric pressure is 755 mmHg. Has a pressure 12 Kg/cm 2. What is the absolute pressure in Mpa? Answer: B A. 1. B. 1. C. 1. D. 1, 21. A storage tank contains oil with specific gravity of 0 and depth of 20 m. What is the hydrostatic pressure at the bottom of th tank in kg/cm 2? Answer: A A. 1. B. 2. C. 6. D. 3. 22. A batch of concrete consisted of 200 lbs fine aggregate, 350 lbs coarse aggregate, 94 lbs, cement, and 5 gallons water. The specific gravity of the sand and gravel may be taken as 2 and that of the cement as 3/10/ What was the weight of concrete in place per cubic foot? Answer: D A. 172 lbs B. 236 lbs C. 162 lbs D. 153 lbs 23. A batch of concrete consisted of 200 lbs fine aggregate, 350 lbs coarse aggregate, 94 lbs, cement, and 5 gallons water. The specific gravity of the sand and gravel may be taken as 2 and that of the cement as 3. How much by weight of cement is required to produce one cubic yard? Answer: D A. 765 B. 657 C. 675 D. 567 24. A cylindrical tank 2 m diameter, 3 m high is full of oil. If specific gravity of oil is 0, what is the mass of oil in the tank? Answer: A A. 8482 kg B. 4500 kg C. 1800 kg D. 7000 kg 25. 100 g of water are mixed with 150 g of alcohol (w = 790 kg/m 3 ). What is the specific volume of the resulting mixtures, assuming the fluids mixed completely? Answer: D A. 0 cm 3 /kg B. 0 cm 3 /kg C. 0 cm 3 /kg D. 1 cm 3 /kg 26. 100 g of water are mixed with 150 g of alcohol (w = 790 kg/m 3 ). What is the specific gravity of the resulting mixtures, assuming the fluids mixed completely? Answer: D A. 0. B. 0. C. 0. D. 0. 27. A spherical tank is full of water that has a total mass of 10,000 kg. If the outside diameter of the tank is 2722 mm, how thick is the wall of the tank? Answer: B A. 50 mm B. 25 mm C. 30 mm D. 35 mm 28. A cylindrical tank is filled with water at the rate of 5000 gal/min. The height if the water in the tank after minutes is 20 ft. What is the diameter of the tank? Answer: B A. 30 ft B. 25 ft C. 20 ft D. 9 m 29. Water is flowing through a 1 foot diameter pipe at the rate of 10 m/s. What is the volume flow of water flowing? Answer: C A. 7 ft 3 /sec B. 7 ft 3 /sec C. 7 ft 3 /sec D. 0 ft 3 /sec 30. A certain fluid is flowing in a 0 m x 0 m channel at the rate of 3 m/sec
D. 652 m/s 41. A volume of 450 cc of air is measured at a pressure of 740 mm HG absolute and a temperature of 20oC. What is the volume in cc at 760 mm HG abs. and 0 oC? Answer:B A. 516. B. 408. C. 620. D. 375. 42. Assuming compression is according to the law PV = constant. Calculate the initial volume of gas at a pressure of 2 bar which will occupy a volume of 6 cubic meters when it is compressed to a pressure of 42 bar. Answer: A A. 126 m 3 B. 120 m 3 C. 130 m 3 D. 136 m 3 43. How much heat, KJ must be transferred to 20kg of air to increase the temperature from 20 degrees C to 280 degrees C if the pressure is maintained constant. Answer: C A. 2500 B. 2050 C. 5200 D. 5500 44. If air is at pressure, p, of 3200 lb/ft 2. And at a temperature, T, of 800oR, what is the specific volume , v? Answer: B A. 14 ft 3 /lb B. 13 ft 3 /lb C. 11 ft 3 /lb D. 9 ft 3 /lb 45. The mass of air in the room 3m x 5m x 20m is known to be 350 kg. Find its density. Answer: C A. 1 kg/m 3 B. 1 kg/m 3 C. 1 kg/m 3 D. 1 kg/m 3 46. A transportation company specializes in the shipment of pressurized gaseous materials. An order is received for 100 liters of a particular gas at STP (32 oF and 1 atm). What minimum volume tank is necessary to transport the gas at 80 oF and a maximum pressure of 8 atm? Answer: B A. 16 liters B. 14 liters C. 10 liters D. 12 liters 47. A bicycle has a volume of 600 cm 3. It is inflated with carbon dioxide to pressure of 80 psi at 20 oC. How many grams of carbon dioxide are contained in the fire? Answer: A A. 5 g B. 6 g C. 4 g D. 3 g 48. An ideal gas at 0 atm. And 87 oC occupies 0 liters. How many moles are in the sample? (R = 0 atm/mole K) Answer: D A. 0 mole B. 0 mole C. 0 mole D. 0 mole 49. Air compressed in a diesel engine from an initial pressure of 13 psia and a temperature of 120 oF to one twelfth of its original volume. Calculate the final temperature assuming compression to be adiabatic. Answer: D A. 987 B. 980 C. 981 D. 1107 50. The compression ratio of an Otto cycle is 6:1, Psub1 is 14 psia, Tsub1 is 68oF. Find the pressure and temperature at state 2. Answer: D A. 180 psia, 1081 oF B. 180 psia, 139 oF C. 180 psia, 139 oF D. 180 psig, 1081 oR 51. An automobile tire is inflated to 30 psig pressure at 50oF. After being driven, the temperature rise to 75oF. Determine the final gage pressure assuming the volume remains constant. Answer:A A. 32 psig B. 55 psig C. 0 psig D. 38 psig 52. If 10 m 3 of atmospheric air at zero degrees centigrade temperature are compressed to a volume of 1 m 3 at 100 oC, what will be the pressure of air in kpa? Answer: B A. 1500 B. 1384 C. 2000 D. 1000 53. If 8 lbs of a substance receives 240 Btu of heat at constant colume and undergo a tempearure change of 150 oF/ What is the average specific heat of the substance during the process?
Answer: D A. 0 Btu/lb-oF B. 0 Btu/lb-oF C. 0 Btu/lb-oF D. 0 Btu/lb-oF 54. A certain gas at 101 kpa and 16oC whose volume is 2 m 3 are compressed into a storage vessel of 0 m 3 capacity. Before admission, the storage vessel contained the gas at a pressure and temperature at 137 kpa and 24oC; after temperature of the gas in the vessel in Kelvin? Answer: B A. 298. B. 319. C. 180. D. 420. 55. The temperature of an ideal gas remains constant while the absolute pressure changes from 103 kpa to 827 kpa. If the initial volume is 80 liters, what is the final volume? Answer:B A. 100 li B. 10 li C. 8 li D. 1000 li 56. What is the density of air under standard condition: Answer: C A. 1 kg/m 3 B. 1 kg/m 3 C. 1 kg/m 3 D. 1 KN/m 3 57. What is the specific volume of an air at 30 oC and 150 kpa? Answer: D A. 1 m 3 /kg B. 0 m 3 /kg C. 1 m 3 /kg D. 0 m 3 /kg 58. The compression ratio of an Otto cycle is 5. If the initial pressure is 100 kpa, determine the final pressure. Answer: B A. 1000 kpa B. 952 kpa C. 300 kpa D. 100 kpa 59. How much work is done when 20 ft 3 of an air is initially at a pressure of 15 psia and a temperature of 40oF experience an increase of pressure to 80 psi while volume remains constant? Answer: C A. 1000 Btu B. 3000 Btu C. Zero D. 2000 Btu 60. A perfect gas has a value of R = 58. ft-lb/lb-oR and k = 1. Btu are added to 5 lbs of this gas at constant volume when initial temperature is 90oF, find the initial temperature. Answer: B A. 100 oF B. 104 oF C. 154 oF D. 185 oF 61. While the pressure remains constant and 689 kpa, the volume of air changes from 0 m 3 to 0 m 3. What is the work done? Answer: A A. -196 KJ B. 204 KJ C. 206 KJ D. -406 KJ 62. During the polytropic process of an ideal gas, the state changes from 20 psia and 40 oF to 120 psia and 340oF. Determine the value of n. Answer: C A. 1. B. 1. C. 1. D. 1. 63. A group of 50 persons attend a secret meeting in a room which is 12 meters wide by 10 meters long and a ceiling height of 3 m. The room is completely sealed off and insulated. Each person gives off 120 kcal per hour of heat and occupies a volume of 0 m 3. The room has an initial pressure of 101. kpa and temperature of 16oC. Calculate the room temperature after 10 minutes. Answer: B A. 36. B. 33. C. 23. D. 76. 64. The compression ratio of an ideal Otto cycle is 6:1. Initial conditions are 101 kpa and 20 oC. Find the pressure and temperature at the end of adiabatic compression. Answer: A A. 1244 kpa, 599 B. 1244 kpa, gage, 60 oC C. 1244 kpa, 60oC D. 1244 kpa, 599 65. Ammonia weighing 22 kgs is confirmed inside a cylinder equipped with a piston has an initial pressure of 413 kpa and 38oC. If 2900 KJ if heat is added to the ammonia until its final pressure and temperature are 413 kpa and 100oC, respectively, what is the amount of work done bt rhe fluid in
B. Quadruples C. Remains constant D. Halves 78. What horsepower is required to isothermally compress 800 ft 3 of air per minute from 14 psia to 120 psia? Answer: D A. 13900 Hp B. 28 Hp C. 256 Hp D. 108 Hp 79. An ideal gas at 45 psig and 80oF is heated in a closed container to 130oF. What is the final pressure?Answer 80. A Carnot engine requires 35 KJ/sec from the hot source. The engine produces 15 kw of power ant the temperature of the sink 26oC. What is the temperature of the hot source? Answer C A. 245. B. 210. C. 250. D. 260. 81. A Carnot engine receives 130 Btu of heat from a hot reservoir at 700oF and rejects 49 Btu of heat. Calculate the temperature of the cold reservoir. Answer: D A. -21 B. -24 oF C. -20 oF D. -22 oF 82. The maximum thermal efficiency possible for a power cycle operating between 1200 oF and 225 oF is: A. 58% B. 58% C. 57% D. 57% 83. A heat engine is operated between temperature limits of 1370oC and 260 oC. Engine supplies with 14,142 KJ per KWH. Find the Carnot cycle efficiency in percent: C A. 70. B. 65. C. 67. D. 69. 84. An Otto cycle has clearance volume of 7%. It produces 300 kw power. What is the amount of heat rejected in KW? Answer: C A. 170 B. 160 C. 152 D. 145 85. A closed vessel contains air at a pressure of 160 KN/m 2 gauge and temperature of 30oC. The air is heated at constant volume of 60oC with the atmospheric pressure as 759 mm Hg. What is the final gauge pressure? Answer: C A. 174 B. 169 C. 185. D. 172 86. An air standard engine has a compression ratio of 20 and cut-off ratio of 5. If the intake air pressure and temperature are 100 kpa and 27oC, find the work in KJ per kg. Answer: B A. 2976 B. 2166 C. 2437 D. 2751 87. The thermal efficiency of a particular engine operating on an ideal cycle is 35%. Calculate the heat supplied per 1200 watt-hr of work developed in KJ. Answer:A A. 12343 B. 10216 C. 14218 D. 11108 88. In an air standard Otto cycle, the clearance volume is 18% of the displacement volume. Find the compression ratio and or thermal efficiency. Answer: C A. 0. B. 0. C. 0. D. 0. 89. The clearance of a diesel cycle is 1%. If initial temperature is 27oC, determine the final temperature. Answer: A A. 510 oC B. 610 oC C. 540 oC D. 1000 oC 90. For an ideal cycle with overall value of k = 1, compression ratio is 15 and cur-off ratio of 2, determine the cycle efficiency: B A. 50% B. 52% C. 46% D. 49% 91. An ideal Otto cycle with 15% clearance operates on 0 kg/sec of air with k = 1. Determine the efficiency of the cycle. Answer: D A. 50% B. 43%
C. 41%
D. 47%
- An ideal Otto cycle, operating in hot air with k = 1 has compression ratio of 5. Determine the efficiency of the cycle. Answer: A A. 42% B. 62% C. 64% D. 36%
- An engine operates on the air standard Otto cycle. The cycle work is 900 KJ/kg, the maximum cycle temperature at the end of isentropic compression is 600 oC. Determine the engines compression ratio. Answer: A A. 6. B. 10. C. 8. D. 7.
- In an air standard diesel cycle,
compression start at 100 kpa and
300 oK. The compression ratio is 16 to
- The maximum cycle temperature is 2031 oK. Determine the cycle efficiency. Answer: C A. 60% B. 56% C. 65% D. 45%
- A diesel engine is operating on a 4- stroke cycle, has a heat rate of 11315. KJ/KW-hr brake. The compression ratio is 13. The cut-off ratio is 2. Using k = 1, what is the brake engine efficiency. Answer: A A. 63% B. 51% C. 73% D. 45%
- Determine the air-standard efficiency of an engine operating on the diesel cycle with clearance of 8% when the suction pressure is 99 kpa and the fuel is injected for 6% of the stroke. Assume k = 1. Answer: D A. 63% B. 51% C. 73% D. 60%
- A heat engine ( Carnot cycle ) has its intake and exhaust temperature if 157 oC and 100 oC, respectively. What is its efficiency? Answer: D A. 12% B. 14% C. 15% D. 13%
- Find the enthalpy of 100 psi and 97% quality, hf = 298 Btu/lb; hfg = 889. Btu/lb. Answer: B A. 1170 Btu/lb B. 1161 Btu/lb C. 1734 Btu/lb D. 1803 Btu/lb
- 180 grams of saturated water of temperature 95 oC undergoes evaporation process until all vapor completely vaporized. Determine the changed in volume. At 95 oC, vf= 0 m 3 /kg. Answer: D A. 0 m 3 B. 0 m 3 C. 0 m 3 D. 0 m 3
- Five kilograms of saturated liquid at kpa is heated until its moisture content is 5%. Find the work done for this process. Answer A A. 813 KJ/kg B. 643 KJ/kg C. 542 KJ/kg D. 753 KJ/kg
- Twenty kilograms of water at 40oC is confined in a rigid vessel. The heat is supplied until all the water is completely vaporized. Find the heat added in KJ. Answer: C A. 45,422 KJ B. 43,122 KJ C. 45,252 KJ D. 65,233 KJ
- Steam at 2 Mpa and 250oC in a rigid cylinder is cooled until the quality is 50%. Find the heat rejected from the cylinder. At 2 Mpa and 250oC V = 0 m 3 /kg u = 2679 KJ/kg At 2 Mpa, (saturated) Vf = 0 m 3 /kg vg = 0 m 3 /kg uf = 906 1693. Answer: B A. -432 KJ/kg B. -926 KJ/kg C. -834 KJ/kg D. 1082 KJ/kg
- At 1 Find the entropy in KJ/kg-K at 90% moisture of a 1 Mpa steam-water mixture? At 1 Mpa:sg = 6 sfg = 4. A. 4. B. 6. C. 2. D. 4.
respectively. What is the increase of entropy of the system in KJ/oC? Answer: C A. 1. B. 0. C. 0. D. 0. 115. Using steam table. Find the enthalpy of steam at kpa if its specific volume is 0 m 3 /kg. Answer: A A. 1625 KJ/kg B. 1785 KJ/kg C. 1543 KJ/kg D. 1687 KJ/kg 116. A throttling calorimeter is connected to the desuoerheated steam line supplying steam to the auxiliary feed pump on a ship. The line pressure measures 2 Mpa. The calorimeter pressure of 137 kpa and 413 kpa and temperature of 27oC and 177oC respectively. What is the increase of entropy of the system in KJ/oC? Answer: C A. 6 KJ/kg-oK B. 7 KJ/kg-oK C. 6 KJ/kg-oK D. 7 KJ/kg-oK 117. Steam enters an isothermal compressor at 400oC and 100 kpa. The exit pressure is 10 Mpa, determine the change of enthalpy. Answer: D A. 198 KJ/kg B. 178 KJ/kg C. 187 KJ/kg D. 182 KJ/kg 118. Steam enters an adiabatic at 300oC and 400 kpa. It exits as a saturated vapor at 30 kpa. Determine the work done. Answer: B A. 476 KJ/kg B. 441 KJ/kg C. 436 KJ/kg D. 524 KJ/kg 119. A 0 m 3 tank contains saturated steam at 300 kpa. Heat is transferred until pressure reaches 100 kpa. Find the final temperature: C A. 94 B. 83 C. 99 D. 103 120. A 500 li contains a saturated mixture of steam and water at 300oC. Determine the mass of vapor if their volumes are equal. Answer: A A. 11 kg B. 10 kg C. 13 kg D. 16 kg 121. A 1 kg steam-water mixture at 1. Mpa is contained in an inflexible tank. Heat is added until the pressure rises to 3 Mpa and 400oC. Determine the heat added. Answer: A A. 1378 KJ B. 1532 KJ C. 1456 KJ D. 1635 KJ 122. Atmospheric pressure boils at 212oF. At the vacuum pressure at 24 in Hg, the temperature is 142oF. Find the boiling temperature when the pressure is increased by 45 psia. Answer: C A. 342 B. 526 C. 479 D. 263 123. What is the temperature in degree C of 2 liters of water at 30 oC after 500 calories of heat have been added to? Answer: B A. 35. B. 30. C. 38. D. 39. 124. A mass of 0 kg metal having a temperature of 100 oC is plunged into 0 kg if water at 20 oC. The temperature of the water and metal becomes 48oC. The latent heat of ice at 0 oC is 335 KJ- oK, Assuming no heat loss to the surroundings, determine the specific heat capacity of the metal in KJ/kg-oK. Answer: D A. 0. B. 0. C. 0. D. 0. 125. What is the total energy required heating in raising the temperature of a given amount of water when the energy applied is 1000 KWH with heat losses of 25%? Answer: C A. 1000 B. 1500 C. 1333 D. 1250 126. A 30 kg iron was put in a container with 14 kg water. The water is at 10 oC and the iron has an initial temperature of 439 oK until the iron was in thermal equilibrium with water. Find the change in entropy. (Cp = 0. KJ/kgoK) Answer: D A. -12 KJ/oK B. -43 KJ/oK C. -25 KJ/oK D. -6 KJ/oK
FUELS & COMBUSTION
- A diesel power plant consumes 650 liters of fuel at 26 oC in 24 hours with 28 oAPI. Find the fuel rate in kg/hr. Answer: A A. 23. B. 24. C. 22. D. 26.
- A boiler burns fuel oil with 15% excess air. The fuel oil may be represented by C 14 H 34. Calculate the molal air fuel ratio. Answer: B A. 14 B. 117. C. 102. D. 17.
- A diesel power plant uses fuel that has a density of 892 kg/m 3 at 15. Find the heating value of fuel. Answer: A A. 44,900 KJ/kg B. 19,301 Btu/lb C. 43,000 KJ/kg D. 4356 KJ/kg
- A certain coal has the following ultimate analysis: C = 69% N 2 = 5% H 2 = 2% S = 7% Moisture = 8% O 2 = 3% Ash = 5% Determine the heating value of fuel used: A A. 26,961 KJ/kg B. 45,256 KJ/kg C. 25,002 KJ/kg D. 26,000 KJ/kg
- A diesel power plant uses fuel with heating value of 45,038 KJ/kg. What is the density of fuel used at 30°C? Answer: D A. 0 kg/li B. 0 kg/li C. 0 kg/li D. 0 kg/li
- A diesel engine consumed 945 liter of fuel per day at 30°C. If the fuel was purchased at 15°C and 30° API at P5/li, determined the cost of fuel to operate the engine per day. Answer: B A. P5677. B. P4677. C. P4888. D. P5000.
- A cylindrical tank 3 m long and 2 m diameter is used for oil storage. How many days can the tank supply the engine having 27° API with fuel consumption of 60 kg/hr. Answer: B A. 4. B. 5. C. 7. D. 8.
- Determine the minimum volume of day tank in m 3 of 28° API fuel having a fuel consumption of 200 kg/hr. Answer: B A. 10 m 3 B. 5 m 3 C. 6 m 3 D. 7 m 3
- Given the following ultimate analysis: C = 70% O 2 = 4% N 2 = 5% S 2 = 6% Moisture = 8% H 2 = 3% Ash = 5% Using 25% excess air, determine the actual air fuel ratio. Answer: A A. 11. B. 24. C. 23. D. 26.
- A 650 Bhp diesel engine uses fuel oil of 28° API gravity, fuel consumption is 0 lb/Bhp-hr. Cost of fuel is P7. per liter. For continuous operation, determine the minimum volume of cubical day tank in cm 3 , ambient temperature is 45°C. Answer: A A. 5,291,880 cm 3 B. 5,391,880 cm 3 C. 5,491,880 cm 3 D. 5,591,880 cm 3
- A 650 Bhp diesel engine uses fuel oil of 28° API gravity, fuel consumption is 0/Bhp-hr. Cost of fuel is P7. per liter. For continuous operation, determine the cost of fuel per day at 45°C. Answer: B A. P42,870. B. P42,070. C. P42,570. D. P42,170.
- A logging firm in Isabela operates a Diesel Electric Plant to supply its electric energy requirements. During a 24 hour period, the plant consumed 250 gallons of fuel at 80°F and produced 2700 KW-Hrs. Industrial fuel used is 30° API and was purchased at P3/at 60°F. Determine cost of fuel
composition: C = 71% H = 5% O = 7% N = 1. S = 3% Ash = 8% W = 3% Determine the theoretical weight of Oxygen in lb/lb of coal. Answer: C A. 2. B. 3. C. 2. D. 6. 24. There are 20 kg of flue gases formed per kg of fuel oil burned in the combustion of a fuel oil C 12 H 26. What is the excess air in percent?Answer: A A. 26% B. 18% C. 12% D. 20% 25. A gaseous fuel mixture has a molal analysis: H 2 = 14% CH 4 = 3% CO = 27% O 2 = 0% CO 2 = 4% N 2 = 50% Determine the air-fuel ratio for complete combustion on molal basis: C A. 2. B. 3. C. 1. D. 1. 26. A steam generation burns fuel oil that has the following chemical analysis by mass in percent: Answer: C C = 85 H 2 = 14. S = 0. N 2 = 0. A. 19. C. 17. B. 11. D. 14. 27. Calculate the theoretical air needed for the complete combustion of ethane C 2 H 6 for 20 kg fuel. Answer: D A. 432 kg B. 287 kg C. 234 kg D. 320 kg 28. A fuel oil burned with 50 percent excess air, and the combustion characteristics of the fuel oil are similar to C 12 H 26. Determine the volumetric (molal) analysis of CO2 in the production of combustion. Answer: B A. 9%
B. 8%
C. 6%
D. 7%
- Fuel oil, C 12 H 26 is burned in air at atmospheric pressure. The Orsat analysis of the products of combustion yields. CO 2 : 12% O 2 : 3% CO : 0% N 2 : 83% Determine the percent excess air. Answer: C A. 12% B. 8% C. 10% D. 18%
- unknown fuel has the following Orsat analysis: CO 2 : 12. CO : 0% O 2 : 3% N 2 : 84% Determine the actual air – fuel in kg air per kg fuel. Answer: A A. 17. B. 12. C. 19. D. 23.
- What mass of liquid oxygen is required to completely burned 1000kg of liquid butane, C 4 H 10 on a rocket ship? Answer: C A. 4568 B. 2746 C. 3586 D. 6345
- A volumetric analysis of a gas mixture is as follows: CO2 : 12% O 2 : 4% N 2 : 82% CO : 2% What is the percentage of CO on a mass basis? Answer: D A. 1% B. 1% C. 1% D. 1%
- What is the percent theoretical air for a combustion process to which the fuel and combustion gas analysis are known as follows:Answer: A Fuel: % by volume CO2: 12% CO: 27% H 2 : 2% N 2 : 58% Combustion gas: % by volume CO 2 : 24%
O 2 : 1%
H 2 : 74%
A. 111
B. C.
C. 121
D.
VARIABLE LOAD
- A 50 MW power plant has an average load of 31,500 KW and a factor of 70%. Find the reserve over peak. Answer: C A. 4 MW B. 3 MW C. 5 MW D. 6 MW
- The daily energy produced in a certain power is 280,000 KW – hrs. What is the daily average load? Answer: D A. 10 MW B. 15 MW C. 25 MW D. 20 MW
- The annual energy produced in a 100 MW power plant is 438,000,000 KW – hrs. What is the annual capacity factor of the plant? Answer: B A. 40% B. 50% C. 35% D. 60%
- A power plant has a use factor of 50% and factor of 44%. How many hours did it operate during the year? Answer: C A. 7700 hrs. B. 7800 hrs. C. 7709 hrs. D. 7805 hrs. STEAM CYCLE
- In a Rankine cycle steam enters the turbine at 2 Mpa (enthalpies & entropies given) and condenser of 50 Kpa (properties given), what is the thermal efficiency of the cycle. Answer A At 2 Mpa: hg = 2803 KJ/kg s g = 6. At 50 kpa: sf = 1 s fg = 6. hf = 340 hfg = 2305. vf = 0. A. 25% B. 45% C. 34% D. 12%
- In an ideal Rankine cycle, the steam throttle condition is 4 Mpa and 4400 C. If turbine exhaust is 0 Mpa, determine the pump work in Kj per kg. Answer C A. 6. B. 5. C. 4. D. 2.
- A thermal power plant generates 5 MW has also 300 OW power needed for auxiliaries. If the heat generated by fuel is 13,000 KJ/sec, determine the net thermal efficiency. Answer B A. 35% B. 36% C. 30% D. 33.
- In an ideal Rankine cycle, the steam throttle condition is 4 Mpa and 4400 C. If turbine exhaust is 0 Mpa, determine the thermal efficiency of the cycle. Answer B A. 20% B. 27% C. 34% D. 43%
- In a Rankine cycle, saturated liquid water at 1 bar is compressed isentropically to 150 bar. First by heating in a boiler, and then by superheating at constant pressure of 150 bar, the water substance is brought to 7500 K. After adiabatic reversible expansion in a turbine to 1 bar, it is then cooled in a condenser to saturated liquid. What is the thermal efficiency of the cycle(%)?Answer C A. 23% B. 16% C. 34% D. 18%
- A steam generating plant has two 20 MW turbo-generators. Steam is supplied at 1 Mpa and 3200 C. Exhaust is 0 MPa. Daily average load factor is 80%. The steam generating units operate at 70% efficiency when using bunker fuel having a heating value of 31, KJ/kg and an average steam rate of 5 kg steam/KW-hr. Calculate the Mtons of fuel oil/bunker fuel required per 24 hours. Answer A A. 515 B. 432 C. 6. D. 762
- A back pressure steam turbine of 100,000 KW serves as a prime mover in a cogeneration system. The boiler admits the return water at a temperature of 660 C and produces the steam at 6 Mpa and 455 0 C. Steam then enters a back pressure turbine and expands to the pressure of the process,
leaves with an enthalpy of 160 KJ/kg. Cooling water passes through the condenser with temperature increases from 13 degrees C to 24 0 C/ Calculate the water flow rate in kg/s. Answer C A. 533 B. 518 C. 523 D. 528 16. In an open feedwater heater for a steam plant, saturated steam at 7 bar is mixed with subcooled liquid at 7 bar and 250 C. Just enough steam is supplied to ensure that the mixed steam leaving the heater will be saturated liquid at 7 bar when heater efficiency is 90%. Calculate the mass flow rate of subcooled liquid if steam flow rate is 0 kg/s. Steam Properties are: Answer A At 7 bar, saturated vapor: hg = 2763 KJ/kg At 7 bar, and 25 0 C: hf = 105 KJ/kg At 7 bar, saturated liquid: hf = 697 KJ/kg A. 2. B. 3. C. 2. D. 3. ` 17. Steam expands adiabatically in a turbine from 2000 Kpa, 4000 C to 400 Kpa, 250 0 C. What is the effectiveness of the process in percent assuming an atmospheric pressure of 150 C. Neglect changes in kinetic and potential energy. Answer C Steam Properties are: At 2000 Kpa and 4000C. h = 3247. KJ/kg s = 7 KJ/kg-K At 400 Kpa and 2500C. h = 2964 KJ/kg s=7 KJ/kg- K A. 82 B. 84 C. 80 D. 86 19. Steam enters the turbine of a cogeneration plant at 0 Mpa and 5000 C. Steam at a flow rate of 7 kg/s is extracted from the turbine at 600 Kpa pressure for process heating. The remaining steam continues to expand to 10 Kpa. The recovered condensates are pumped back to the boiler. The mass flow rate of steam that enters the turbine is 30 kg/s. Calculate the cogeneration efficiency in percent. Answer No exact answer in the choices Steam Properties At 7 Mpa and 500 0 C: h = 3410. s = 6. At 600 Kpa: hf = 670. hfg = 2086. sfg = 4. At 10 Kpa: hf = 191. hfg = 2392. sf = 0. sfg = 7. A. 60 B. 50 C. 65 D. 55 20. A heat exchanger was installed purposely to cool 0 kg of gas per second. Molecular weight is 28 and k = 1. The gas is cooled from 150 0 C to 80 0 C. Water is available at the rate of 0 kg/s and at a temperature of 120 C. Calculate the exit temperature of the water in 0 C. Answer A A. 48 B. 42 C. 46 D. 44 21. Pump work of Rankine cycle is 15 KJ/kg. Density of water entering the pump is 958 kg/m 3. If condenser pressure is 100 Kpa, what is the pressure at the entrance of the turbine? Answer A A. 14 Mpa B. 20 Mpa C. 15 Mpa D. 17 Mpa 22. In a Rankine cycle the turbine work is 1,000 KJ/kg and pump work of 13 KJ/kg. If heat generated by generator is 2800 KJ/kg, what is the efficiency of the cycle? Answer A A. 35% B. 4% C. 38% D. 30% 23. In a Reheat power plant the difference in enthalpy at the entrance and exit is 550 KJ/kg for first stage and second stage is 750 KJ/kg. If both stages has an efficiency of 92% and heat added to boiler is 3,000 KJ/kg. Determine the plant cycle efficiency neglecting the pump work. Answer C A. 30% B. 35% C. 40% D. 45% 24. An adiabatic feed pump in a steam cycle delivers water to a steam generator at a temperature of 200 0 C and a pressure of 10 Mpa. The water
eneters the pump as a saturated liquid at 1800 C. If the power supplied to the pump is 75 kW, determine the mass flow rate. Answer C A. 6 kg/s B. 8 kg/s C. 7 kg/s D. 9 kg/s 25. A condenser receives steam from a turbine at 15 kPa, 90% quality, and with a velocity of 240 m/s. Determine the increase in circulating water required because of high pressure exit velocity if the steam flow rate is 38 kg/s and the cooling water temperature rise is12 0 C with an inlet condition of 300 C. Answer D A. 11 kg/s B. 17 kg/s C. 13 kg/s D. 21 kg/s 26. A steam generator has an exit enthalpy of 3195 KJ/kg at the rate of 10 kg/s. The enthalpy available at the turbine inlet is 3000 KJ/kg. Determine the heat lost between boiler outlet and turbine inlet. Answer B A. 1957 kW B. -1957 kW C. 1873 kW D. -1873 kW 27. A Rankine cycle has a turbine with available enthalpy of 800 KJ/kg. The pump has also 10 KJ/kg energy available. Find the net cycle output of the plant if mass flow rate is 5 kg/s. Answer B A. 2619 kW B. 3950 kW C. 8745 kW D. 4234 kW 28. A Rankine cycle, the steam is extracted from the turbine at 2 Mpa and 250 0 C for feedwater heating and it is mixed with condenser exit at 30 Kpa after pumping. Find the fraction of vapor extracted from the turbine. Answer A A. 0. B. 0. C. 0. D. 0. 29. An adiabatic turbine in a steam generating plant receives steam at a pressure of 7 Mpa and 550 0 C and exhausts at 20 kPa. The turbine inlet is 3 m higher than the turbine exit, the inlet steam velocity is 15 m/s and the exit is 300 m/s. Calculate the turbine work in KJ/kg. Answer B A. 1297.
B. 1197.
C. 1093.
D. 1823.
- A steam power plant operates on the Rankine cycle. The steam enters the turbine at 7 Mpa and 550 0 C with a velocity of 30 m/s. It discharge to the condenser at 20 kpa with a velocity of 90 m/s. Calculate the net work in kW for a flow of 37 kg/s. Answer D A. 23 MW B. 53 MW C. 34 MW D. 46 MW
- A Carnot cycle uses steam as the working substance and operates between pressure of 7 Mpa and 7 kpa. Determine the cycle thermal efficiency. Answer A A. 44% B. 54% C. 34% D. 59%
- A supercritical power plant generates steam at 25 Mpa and 5600 C. The condenser pressure is 7 kpa. Determine the exit quality of steam if it expands through a turbine in this power plant. Answer D A. 45% B. 68% C. 56% D. 74%
- Steam enters a turbine at 1 Mpa and 3200 C. The turbine internal efficiency is 70%, and the total requirement is 800 kW. The exhaust is to the back pressure system, maintained at 175 kpa. Find the steam flow rate. Answer A A. 2 kg/s B. 4 kg/s C. 3 kg/s D. 5 kg/s BOILERS
- The heating surface are of water tube boiler is 200 m 2 , what is the equivalent rated boiler horsepower? Answer D A. 217 Hp B. 2365 Hp C. 200 Hp D. 219 Hp
- The rated boiler horsepower of a fire tube boiler is 500 Hp. What is the heating surface area of the boiler? Answer D A. 500 m 2 B. 300 m 2 C. 400 m 2 D. 550 m 2
evaporation is 1, boiler rating is 200%, boiler efficiency is 5%, heating surface area is 0 m 2 /boiler Hp, and the heating value of fuel is 18, Kcal/kg. The total coal available in the bunker is 50,000 kg. Determine total number of hours to consume the available fuel. Answer D A. 533. B. 743. C. 634. D. 853. 14. A boiler operating at 11 kg/cm 2 is required to generate a minimum of 50,000 kj/hr of saturated steam. Feed water enters the boiler at 800 C. Compute the fore coal at an average rate 4,800 kg/hr and boiler efficiency is 85%. Compute the minimum heating value of local coal that could be used in order to ensure the generation of required steam. Answer B A. 28, B. 29, C. 23, D. 30, 15. A boiler operating at 11 kg/cm 2 is required to generate a minimum of 50,000 kg/hr of saturated steam. Feed water enters the boiler at 80 0 C. The furnace is designed to fire coal at an average rate 4,800 kg/hr and boiler efficiency is 85%. Compute the developed boiler horsepower. Answer A A. 3462 hp B. 1234 hp C. 2345 hp D. 4233 hp 16. A steam boiler generating 7 kg/s of 4 Mpa, 426 0 -C steam is continuously blown at the rate of 0. kg/sec. Feed water enters the economizer at 149 0 C. The furnace burns 0 kg coal/sec of 30,470. KJ/kg higher heating value. Calculate the overall thermal efficiency of steam boiler. Answer C A. 76% B. 84% C. 82% D. 88% STEAM ENGINE
- A steam engine has 10% brake thermal efficiency and delivers 750 kg/hr steam. The enthalpy of engine entrance is 2800 KJ/kg and condenser exit is 450 KJ/kg. Determine the brake power of the engine. Answer C A. 46 KW B. 47 KW
C. 49 KW
D. 48 KW
- The indicated efficiency of a steam engine is 60%. The engine entrance is 2700 KJ/kg and exit is 2000 KJ/kg. If steam consumption is 800 kg/hr and mechanical efficiency is 90%, what is the brake power of the engine? Answer B A. 55 KW B. 84 KW C. 65 KW D. 70 KW
- A steam engine has bore and stoke of 300 mm x 420 mm running at 250 rpm has mean indicated pressure of the engine is 400 Kpa. Determine the indicate power. Answer D A. 100 KW B. 50 KW C. 65 KW D. 99 KW
- The crank shaft of a double acting steam engine rotates at 220 rpm. The bore and stroke of the steam engine is 300 mm x 450 mm, and the mean effective pressure acting upon the piston is 4 kg/cm 2. Find the indicated horsepower developed in the cylinder. Answer A A. 122 hp B. 110 hp C. 143 hp D. 176 hp
- A steam engine develops 60 Bhp with dry saturated steam at 1034 Kpa absolute and exhaust at 124 Kpa. Steam consumption is 736 kg/hr. Calculate the indicated engine efficiency based on 90% mechanical efficiency. Answer D A. 34% B. 54% C. 45% D. 66%
- A steam engine develops 60 Bhp with dry saturated steam at 1034 Kpa absolute and exhaust at 124 Kpa. Steam consumption is 736 kg/hr. calculate the thermal efficiency of equivalent Rankine engine. Answer A A. 15% B. 34% C. 12% D. 21%
- A 350 mm x 450 mm engine running at 260 rpm has an entrance steam condition of 2 Mpa and 230 0 C and exit at 0 Mpa. The steam consumption is
2,000 kg/hr and mechanical efficiency is 88%. If indicated mean effective pressure is 600 Kpa, determine the brake thermal efficiency. Answer C A. 23% B. 18% C. 14% D. 27% 8. A 350 x 450 mm engine running at 260 rpm has an entrance steam condition of 2 Mpa and 230 0 C and exit at 0 Mpa. The steam consumption is 2,000 kg/hr and mechanical efficiency is 88%. If indicated mean effective pressure is 600 Kpa, determine indicated thermal efficiency. Answer A A. 16% B. 34% C. 12% D. 21% 9. Steam is admitted to the cylinder of an engine in such a manner that the average pressure is 120 psi. The diameter of the piston is 10” and the length of stroke is 12”. Answer D A. 171. B. 175 C. 173. D. 174. STEAM TURBINE
- A steam turbine receives 5,000 kg/hr of steam at 5 Mpa and 400 0 C and velocity of 25 m/sec. It leaves the turbine at 0 Mpa and 85% quality and velocity of 20 m/sec. Radiation is 10,000 KJ/hr. Find the KW developed. Answer C A. 1273. B. 2173. C. 1373. D. 7231.
- An industrial power plant requires 1. kg of dry saturated steam per second at 1650 C for heating purposes. This steam may be supplied from an extraction turbine which receives steam at 4 Mpa and 3800 C and is exhaust to condenser at the rate of 0. kg steam per second at 0 Mpa while rejecting 1400 KW to the cooling water. If mechanical-electrical efficiency is 95% and that the heat loss in the turbine casing is 10 KW, calculate the power generated by the plant. Answer B A. 2,126 KW B. 1,556 KW C. 3,123 KW D. 4,344 KW
- A steam turbine with 90% stage efficiency receives steam at 7 Mpa and 5500 C and exhausts as 20 Kpa. Determine the turbine work. Answer A A. 117 KJ/kg B. 132 KJ/kg C. 123 KJ/kg D. 143 KJ/kg
- A steam turbine with 90% stage efficiency receives steam at 7 Mpa and 5500 C and exhausts as 20 Kpa. Determine the quality at exhaust. Answer D A. 87% B. 76% C. 82% D. 91%
- A small steam turbine power plant of 5,000 KW capacity has a full load steam rate of 6 kg steam pwer KW-hr. No load steam consumption may be taken as 10% of the full load steam consumption. Write the equations of WILLANS LINE of this turbine and at 60% of rated load, calculate the hourly steam consumption of this unit. Answer C A. 19,100 kg/hr B. 19,300 kg/hr C. 19,200 kg/hr D. 19,400 kg/hr
- Steam flows into a turbine at the rate of 10 kg/sec and 10 KW of heat are lost from the turbine. Ignoring elevation and kinetic energy effects, calculate the power output from the turbine. Inlet enthalpy is 2739 KJ/kg and exhaust enthalpy is 2300 KJ/kg. Answer C A. 4605 KW B. 4973 KW C. 4375 KW D. 4000 KW
- Steam entering the turbine has a rate of 10 kg/sec with enthalpy of 3400 KJ/kg and 2600 KJ at the exhaust. If 100 KW of heat is rejected from turbine casing, what is the turbine work? Answer A A. 7900 kW B. 7700 KW C. 5600 KW D. 5400 KW
- A steam turbine of 6 MW capacity has a Willian’s line equation of ms = 5
- 3,000 kg/hr. Determine the steam consumption at 70% load. Answer C A. 3564 kg/hr B. 3546 kg/hr C. 26,100 kg/hr D. 58,000 kg/hr
PIPE Review materials
Course: Mechanics Of Fluids (MECH 40A)
University: University of Cebu
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