The following data were obtained on a diesel engine operatin

The following data were obtained on a diesel engine operating in a prony brake. a. Compute the brake horespower at each engine speed. Answer: 319.9, 295.1, 251.3, and 194.2 hp. b. Compute the overall engine efficiency at each engine speed. Answer: 0.235, 0.278, 0.297, and 0.298. c. Compute the fuel consumption in gallons per day for an average engine speed of 800 rpm and a 12-hour work day. Answer: 188.4 gal/D. Compute the tension in the fast line when lifting a 500,000 lbf load for 6, 8, 10, and 12 lines strung between the crown block and traveling block. Answer: 95, 347; 74, 316; 61, 728; and 54, 113 lbf. A rig must hoist a load of 200,000 lbf. The drawworks can provide a maximum input power of 800 hp. Ten lines are strung between the crown block and the traveling block and the dead line is anchored to a derrick leg on one side of the v-door (Fig. 1.17). a. Calculate the static tension in the fast line when upward motion is impending. Answer: 24, 691 lbf b. Calculate the maximum hook horsepower available. Answer: 648 hp. c. Calculate the maximum hoisting speed. Answer: 10639 ft/min. d. Calculate the derrick load when upward motion is impending. Answer: 244, 691 lbf. e. Calculate the maximum equivalent derrick load. Answer: 280,000 lbf. f. Calculate the derrick efficiency factor. Answer: 0.874 Compute the minimum time required to reel a 10,000 - ft cable weighing 1 lbf/ft to the surface using a 10-hp engine. Answer: 151.5 min. A 1.25-in drilling line has a nominal breaking strength of 138, 800 lbf. A hook load of 500,000 lbf is anticipated on a casing job and a safety factor based on static loading conditions of 2.0 is required. Determine the minimum number of lines between the crown block and traveling block that can be used. Answer: 10. A driller is pulling on a stuck drillstring. the derrick is capable of supporting a maximum equivalent derrick load of 500,000 lbf. the drilling line has a strength of 51, 200 lbf. and the strength of the drillpipe in tension is 396,000 lbf. If eight lines are strung between the crown block and traveling block and safety factors of 2.0 are required for the derrick, drillpipe, and drilling line. how hard can the driller pull trying to free the stuck pipe? Answer: 166, 667 lbf. A rig acceleratges a load of 200,000 lbf from zero to 60 ft/min in 5 seconds. Compute the load shown on the hook load indicator. Answer: 201, 242 lbf A load of 400,000 lbf is lowered a distance of 90 ft using the auxiliary drawworks brakes. Compute the heat that must be dissipated by the brake cooling system. Answer: 46, 213 Bru A drawworks drum has a diameter of 30 in., a width of 56.25 in., and contains 1.25 in- drilling line Calculate the approximate length of line to the first lap point. Answer: 368.2 ft. For the drawworks drum dimensions given in Exercise 1.9 and a fast line tension of 50,000 lbf. Compare the drawworks torque when the drum contains five laps. Answer: 65, 104 ft-lbf empty: 85, 938 ft-lbf with five laps. Consider a triplex pump having 6-in liners and 11-in. Strokes operating at 120 cycles/min and a discharge pressure of 3,000 psig. a. Compute the pump factor in units of gal/cycle at 100% volumetric efficiency. Answer: 4.039 gal/cycle. b. Compute the flow rate in gal/min. Answer 484.7 gal/min. C. Compute the energy extended by each piston

Solution

1. Brake power in kW = 2*pi*N*T/60*1000 = 2*3.14*1200*(1898 N.m)/60*1000 = 238.38 kW = 319.9 hp

2*3.14*1000*2101.5/60000 = 219.957kW = 295.1 hp

2*3.14*800*2237/60000 = 251.3 hp

2*3.14*600*2305/60000 = 194.2 hp