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ME 10 Fluid MachineryQuiz Assignment 7CompressorDirection: Write the Sample Compressor Problem in a clean Short Bond Paper. Take a photo and save/paste in a common file.Problem 1A compressor of a compressed air system displaces air at 25 cubic meters per minute when the intake pressure is 101 kPa. C...

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ME 10 Fluid Machinery Quiz Assignment 7 Compressor Direction: Write the Sample Compressor Problem in a clean Short Bond Paper. Take a photo and save/paste in a common file. Problem 1 A compressor of a compressed air system displaces air at 25 cubic meters per minute when the intake pressure is 101.4 kPa. Compute the time required to pump up a 9-cubic meter receiver from 550 kPa to 828 kPa if the average volumetric efficiency of the compressor is 70%. A. 1.95 minutes C. 1.41 minutes B. 2.84 minutes D. 1.82 minutes

Problem 2 The compressor of a compressed air system displaces air at 22.7 cubic meters per minute at an intake pressure of 101 kPa and a discharge pressure of 828 kPa. Compute the required minimum receiver volume. A. 2.80 m3/min C. 94 m3/min B. 8.50 m3/min D. 185 m3/min

Problem 3 The pressure of air in the air receiver is 1035 kPa and has a 4450 N force. Determine the piston diameter that can support this force. A. 7.39 cm C. 11.92 cm B. 10.52 cm D. 9.34 cm

Problem 4 One kilogram of air is compressed adiabatically and in steady flow. The compression efficiency is 80% and work done is 265 kJ/kg. Determine the heat added to the air. A. 212 kJ/kg C. 0 B. 1 kJ/kg D. 331.25 kJ/kg Problem 5 When changes in kinetic energy of a compressed gas are negligible or insignificant, the work input to an adiabatic compressor is . A. negligible C. equal zero B. change in enthalpy D. infinity Problem 6 A R-12 compressor operates between evaporating temp of 4C (hg = 353.18 kJ/kg, vg = 0.04895) and condensing temperature of 43C (hf = 241. 6 kJ/kg). Determine the bore diameter of the 4cylinder, 1000 rpm compressor if the piston speed is 200 meters per minute and actual volumetric efficiency is 82% and refrigeration load is 25 tons. C. 9.5 cm A. 7.5 cm B. 8.5 cm D. 10.5 cm

Problem 7 A simple vapor compression cycle develops 20 tons of refrigeration, which uses ammonia and operates at 24C (hf = 312.87 kJ/kg) condensing temperature and –18C (hg = 1439.94 kJ/kg) evaporating temperature. The enthalpy of the refrigerant after the compression is 1657 kJ/kg. Determine the power per ton of refrigeration. A. 0.4772 kw/ton C. 0.6772 kw/ton B. 0.5772 kw/ton D. 0.7772 kw/ton

Problem 8 An ammonia compressor has a clearance of 5% and a pressure ratio of 5. Determine the volumetric efficiency if k for ammonia is 1.304. A. 82.82 % C. 87.82 % B. 89.82 % D. 85.82 %

ME Board - April 1999 For negative slip, the coefficient of discharge for a positive displacement reciprocating compressor is A. Cd = 1 C. Cd < 1 B. Cd > 1 D. Cd = 0 Problem 9 A 140 mm  140 mm single effect, twin-cylinder, single-acting Freon 12 compressor with a refrigeration capacity of 40 kw operates between a discharge pressure of 1300 kPa and a suction pressure of 350 kPa. The speed of the compressor is 600 rpm. If the discharge pressure shall be raised to 1400 kPa, at what speed (rpm) should the compressor be run to produce the same refrigeration capacity and assuming the volumetric efficiency to remain the same? Freon 12 Properties: At 350 kPa: h = 189.023 kJ/kg A. 610 C. 620 v = 0.04933 m3/kg B. 615 D. 630 At 1300 kPa: h = 211.314 kJ/kg hf = 87.796 kJ/kg At 1400 kPa: h = 213.692 kJ/kg hf = 91.355 kJ/kg

Problem 10 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. A. 126 cubic meter C. 130 cubic meter B. 120 cubic meter D. 136 cubic meter

Problem 11 A two-stage air compressor operates between constant pressure limits of 98.6 kPa and 1.103 Mpa. The swept volume of the low pressure piston is 0.142 cubic meter. Due to failure of the cooling water supply to the intercooler, air is passed to the high pressure cylinder without reduction in temperature. Using PV1.2 = C, determine the percentage increase in power. A. 26 C. 11 B. 21 D. 16

Problem 12 A large mining company was provided with a 3 cu. meters of compressed air tank. Air pressure in the tank drops from 700 kPa to 180 kPa while the temperature remains unchanged at 28C. What percentage has the mass of air in the tank been reduced?. A. 74 C. 76 B. 72 D. 78

Problem 13 How much work is necessary to compress air in an insulated cylinder from 0.20 cu. m to 0.01 cu. m. Use T = 20C and P1 = 100 kPa. A. 113.4 kJ C. 110.1 kJ D. 115.6 kJ B. 121.4 kJ

Problem 14 An ideal single-stage air compressor without clearance takes in air at 100 kPa with a temperature of 16C and delivered it at 413 kPa after isentropic compression. What is the discharge work done by the compressor in kJ/kg? A. – 59.22 C. – 72.5 B. – 118.4 D. – 145

Problem 15 A single stage air compressor handles 0.454 m3/sec of atmospheric pressure, 27 C air and delivers it to a receiver at 652.75 kPa. Its volumetric efficiency is 0.72, its compression efficiency on an isothermal basis is 0.85 and its mechanical efficiency is 0.90. If it rotates at 350 rpm, what power in kw is required to drive it? A. 95 C. 120 B. 112 D. 100

Problem 16 An air compressor is to compress 8.5 m3 per minute from 98.56 kPa to 985.6 kPa. Assuming conditions ideal, and with n =1.3, what will be the saving in work due to two staging? A. 4.6 kw C. 5.6 kW B. zero D. 3.5 kw

Problem 17 The enthalpy of air is increased by 139.586 kJ/kg in a compressor. The 100 psig rate of air flow is 16.42 kg/min. The power input is 48.2 kW. Which of the following values most nearly equals the heat loss from the compressor in kW? A. – 10.0 C. – 9.95 B. + 10.2 D. + 9.95

Problem 18 A two-stage compressor with first stage piston displacement of 94,390 m3/sec is driven by a motor. Motor output is 35 Hp, suction temperature is 22 C , volumetric efficiency 85%, mechanical efficiency 95%, the intercooler pressure is 30 psi gage. Air temperature in and out of the intercooler are 105C and 44C. Final discharge pressure is 100 psi gage, suction estimated 14.5 psi. Find the compression efficiency. A. 77.68% C. 71.58% B. 67.68% D. 61.58%

Problem 19 A single-acting air compressor operates at 150 rpm with initial condition of air at 97.9 kPa and 27C and discharges the air at 379 kPa to a cylindrical tank. The bore and stroke are 355 mm and 381 mm, respectively with a percentage clearance of 5%. If surrounding air are at 100 kPa and 20C while the compression and expansion processes are PV1.3 = C. Determine the (a) Free air capacity in m3/s (b) power of the compressor in kW....