Fluid Machinery 1 Handouts

Fluid Machinery 1: 1. The suction pressure of a pump reads 3 in. of mercury vacuum and discharge pressure reads 140 psi is use to deliver 120 gpm of water with specific volume of 0.0163 ft3/lb. Determine the pump work. a. 4.6 kW b. 5.7 kW c. 7.4 kW* d. 8.4 kW 2. A submersible pump delivers 350 gpm of water to a height of 5 ft from the ground. The pump were installed 150 ft below the ground level and a drawdown of 8 ft during the operation. If water level is 25 ft above the pump, determine the power. a. 7.13 kW b. 4.86 kW c. 7.24 kW d. 9.27 kW* 3. A double suction centrifugal pumps delivers 20 ft3/sec of water at a head of 12 m and running at 650 rpm. What is the specific speed of the pump? a. 5014.12 rpm b. 6453.12 rpm c. 2770.73 rpm* d. 9968.73 rpm 4. Determine the number of stages needed for a centrifugal pump if it is used to deliver 400 gal/min of water and pump power of 15 Hp. Each impeller develops a head of 30 ft. a. 6 b. 4 c. 5* d. 7 5. A submersible, multi-stage, centrifugal deep well pump 260 gpm capacity is installed in a well 27 feet below the static water level and running at 3000 rpm. Drawdown when pumping at rated capacity is 10 feet. The pump delivers the water into a 25,000 gallons capacity overhead storage tank. Total discharge head developed by pump, including friction in piping is 243 feet. Calculate the diameter of the impeller of this pump in inches if each impeller diameter developed a head of 38 ft. a. 3.28 b. 5.33 c.3.71* d. 6.34 1. A pump delivers 1000 gallons per minute of water at a head of 100 ft. Find the water power needed. a. 12.34 Hp b. 34.12 Hp c. 23.23 Hp d. 25.28 Hp* 2. Find the power of motor needed to pumped the water at a head of 100 m at the rate of 400 lps if pump efficiency is 70%. a. 301.34 kW b. 627.56 kW c. 560.57 kW* d. 426.24 kW 3. A pump has a suction condition of 50 mm Hg vacuum and 50 mm pressure, 100 mm diameter pipe and discharge condition of 250 kPa at 90 mm diameter. The discharge tank is 50 m elevation and the suction is 5 m below the pump center line. If discharge is 0.20 m3/s, find the pump efficiency for 260 kW brake power. a. 74.32%* b. 77.12% c. 79.23% d. 82.45% 4. The suction diameter of 60 mm reads 2 psi vacuum and 50 mm diameter discharge with 250 kpag. The suction water level is 5 m above water pump centerline and discharge water level is 25 m above the pump centerline. The total head loss at suction and discharge is 2 m. if discharge is 0.01 m3/s, find the horsepower needed to pump the water for 80% pump efficiency. a. 6.23 Hp b. 8.15 Hp* c. 16.23 hp d. 12.45 hp 5. The suction water level of a reservoir A is 5 m above pump centerline A and discharge water level is 50m above pump centerline. The discharge is 0.2 m3/s with suction pipe of 100 mm diameter and 90 mm diameter discharge pipe. The total head loss is 50% of the velocity head at suction pipe. If pump runs at 360 rpm, find the torque developed by the shaft of motor if pump efficiency is 76%. a. 3.7 kN-m b. 8.9 kN-m c. 5.4 kN-m* d. 6.7 kN-m 6. A water jet has a diameter of 75 mm and has a velocity of 15 m/s. What is the horsepower exerted by the jet. a. 12 Hp b. 10 Hp* c. 9 Hp d. 8 Hp

7. A pump has a head of 20 m at 450 rpm. What is the increase in head developed by the pump is speed increased to 1000 rpm? a. 43.23 m b. 83.56 m c. 65.23 m d. 78.76 m* 8. The power developed by the pump is 30 kW. What is the percent decrease in power if speed will decrease by 40%. a. 78.4%* b. 90.1% c. 65.3% d. 82.4% 9. A reciprocating pump has 350 mm x 400 mm cylinder running at 360 rpm. If percent slip is 10%, find the volumetric efficiency of the pump. a. 70% b.80% c. 90%* d. 98% 10. A pump develops a power of 50 kW at 300 rpm with fluid specific gravity of 1.02 when impeller diameter is 150 mm. if increases to 650 rpm, impeller diameter of 120 mm and specific gravity of 0.8. Find the new power. a. 130.7 kW* b. 204.19 kW c. 207.23 kW d. 302.23 kW 11. A pump has a specific speed of 42 and 600 rpm when it delivers 0.01 m3/s. find the head developed by the pump. A. 582.45 ft B. 813.45 ft C. 658.69 ft D. 1015.29 ft* 12. A boiler feed pump has a suction enthalpy of 2500 kJ/kg and exit of 505 kJ/kg. Find the velocity of the water in the flowing in the pump. a. 300 m/s b. 50 m/s c. 200 m/s d. 100 m/s* 13. A swimming pool measuring 10 m by 25 m x 2 m is to be filled with water from an artesian well by a motor pump operating with a total dynamic head of 50 m. Assuming an overall motor efficiency of 55%, energy cost of P0.45/kW-hr, find the total cost of energy bill to fill up the swimming pool. a. P23.23 b. P82.34 c. P55.74* d. P132.34 14. A vacuum pump is used to drain a flooded mine shaft of 20C water. The pump pressure of water at this temperature is 2.84 kpa. The pump is incapable of lifting the water higher than 18m. What is the atmospheric pressure? a. 159.30* b. 132.33 c. 198.22 d. 179.4 15. A submersible, multi-stage, centrifugal deep well pump 260 gmp capacity is installed in a well 32 feet below the static water level and running at 3000 rpm. Drawdown when pumping at rated capacity is 10 feet. The pump delivers the water into a 25,000 gallons capacity overhead storage tank. Total discharge head developed by pump, including friction in piping is 243 feet. Calculate the diameter of the impeller of this pump in inches if each impeller diameter developed a head of 36ft. a. 3.68 b. 5.33 c. 3.71* d. 6.34 16. Pump at its best efficiency point (BEP) has a capacity of 12,500 gpm while developing a head of 60ft at a rotative speed of 1450 rpm. What is the specific speed of the pump? a. 2760 b. 1450 c. 7520* d. 6892 17. A radial-flow pump operating at maximum efficiency at a specific speed of 2300 is to deliver 260 gpm against a head of 129 ft a rotative speed of 2100 rpm. Find the required number of stages (i.e., impellers). a. 2 stages b. 3 stages* c. 4 stages d. 5 stages 3 18. A 30Hp pump delivers 475 gpm of gasoline (y = 42.5 lb/ft ) at 20C with 78% efficiency. What pressure rise result across the pump? a. 30.2 psi b. 84.5 psi* c. 120.3 psi d. 73.2 psi 19. A piston positive-displacement pump (PDP) has 8-in diameter and a 2.5-in stroke. Its crankshaft rotates at 300 rpm. Calculate its output at 94 percent volumetric efficiency. a. 12.27 cfm b. 20.51 cfm* c. 10 cfm d. 11.53 cfm 20. A centrifugal pump (efficiency 86%) lifts water through a total height of 42 m from reservoir to discharge. Pumping is through 300m of 75mm diameter pipe at the rate of 20 liter/sec. If the pipe friction factor, f = 0.025, what kW is required? a. 28.4 kW b. 33.4 kW c. 25 kW d. 9 kW*