Journal . 3,000 5,610 5,050 4,550 4,270 4,270 4,500 5,140 4,000 7,480 6,725 6,030 5,590 5,520 5,670 6,250 6,000 11,220 10,051 8,970 8,270 8,000 7,980 8,510 10,000 18,700 16,750 14,850 13,600 13,000 12,650 13,000 Note.—The values in italics shew the best number of stages for that diameter of wheel, speed, and power. Take Rating at 250 One wheel. V = 4,365 ft. per sec. r = 0-1835. rj = 0-535. Rotation loss J^? = 8-42 258*42Thermo-dynamic power = = 483 U * DoD Two wheels—2nd wheel ^ = 0-89. r = 0-48. V = 1, drop =55-5 stage press =2-16 lb. sq. in. abs. S. =
Journal . 3,000 5,610 5,050 4,550 4,270 4,270 4,500 5,140 4,000 7,480 6,725 6,030 5,590 5,520 5,670 6,250 6,000 11,220 10,051 8,970 8,270 8,000 7,980 8,510 10,000 18,700 16,750 14,850 13,600 13,000 12,650 13,000 Note.—The values in italics shew the best number of stages for that diameter of wheel, speed, and power. Take Rating at 250 One wheel. V = 4,365 ft. per sec. r = 0-1835. rj = 0-535. Rotation loss J^? = 8-42 258*42Thermo-dynamic power = = 483 U * DoD Two wheels—2nd wheel ^ = 0-89. r = 0-48. V = 1, drop =55-5 stage press =2-16 lb. sq. in. abs. S. = 135-8 cu. ft. per wheel H = 325. V = 4,030. r = 0-198. v = 0-55. 55-5 X 0-89 +325 x 0-55 Combined efficiency = 380-2Rotation losses, 2nd wheel = 8-42 ,, 1st „ 22-1 = 0-6 30-52 280-52 Thermo-dynamic power = = 468 0-6 216 EXTRACTION TURBINES. WMMMfiA. Wuttahntt&Jfy, Fig. 2. EXTRACTION TURBINES. 217 Three wheels— 2nd and 3rd wheels v = 0-89. H = 111. 1st stage, pressure = 5*72 lb. sq. S, the specific volume,= 56-9. cu. ft. per lb. 1st wheel H = 269-2. V = 3,670. r = 0-218. ?? = 0-59. Ill X 0-89 +269-2 X 0-59 Combined efficiency = = 0-678 380-2 Rotation losses, 2nd and 3rd wheels = 30-52 1st wheel = 52-8 83-32 333•32Thermo-dynamic power = - = 492 Fig. 2.—Section of Reaction Turbine. This illustration shows Parsons first reaction turbine. Byreplacing the wheels by a drum rotation losses are reduced,but other difficulties are involved in end-thrust and steamleakages. The leakage of steam takes place past the balancepistons and over the tops of the blades in the original Parsonsturbine. Due to the large number of blades, it was not foundto be a mechanical device that would stand up against practicalusage. Relative Thermal Efficiencies. This being calculated for a 1,000 K\V. turbine, and assumingthat the w
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