Heat engineering; a text book of applied thermodynamics for engineers and students in technical schools . chest. The velocity is utilizedon one set of blades. To increase the power of the machine anumber of nozzles are used. The angle of the nozzle relative tothe plane of the blade is made as small as possible, as shown inFig. 150, so that the efficiency which is proportional to cos2 ais as large as possible. The peripheral speed of the wheel is very 302 HEAT ENGINEERING great. wa is equal to 3820 ft. per second if the drop in the nozzleis from lbs. gauge to 6 lbs. absolute. The speed of
Heat engineering; a text book of applied thermodynamics for engineers and students in technical schools . chest. The velocity is utilizedon one set of blades. To increase the power of the machine anumber of nozzles are used. The angle of the nozzle relative tothe plane of the blade is made as small as possible, as shown inFig. 150, so that the efficiency which is proportional to cos2 ais as large as possible. The peripheral speed of the wheel is very 302 HEAT ENGINEERING great. wa is equal to 3820 ft. per second if the drop in the nozzleis from lbs. gauge to 6 lbs. absolute. The speed of the wheelfor a value of / of and cos a = would be Wh=zy2X X 3820 = 1719 ft. per sec. This would mean 16,400 for a radius to the blades of 1 pressure drop for the axial distances of nozzle and blade andthe absolute velocity changes are shown in Fig. 151. This figuregives a section through the axis and one parallel to the axis throughthe blades and nozzle. The Curtis turbine is shown in Fig. 152. In this steam entersthe nozzle at A and is discharged against moving vanes. The. Fig. 152.—Section through horizontal Curtis turbine. discharge from these moving vanes is guided by stationary vanesto another set of movable vanes, and after discharge from theseit is taken to another set of nozzles B and discharges into a secondset of vanes. In the figure shown there are five sets of nozzles,A, B, C, D, and E, and to each of these there are two movableand one fixed set of vanes. The pressure drop takes place infive stages, and there is no drop in pressure over the exhaust space F is connected to the condenser. This actionis better shown in Fig. 153 in which a section through the axis STEAM NOZZLES, INJECTORS, STEAM TURBINES 303 and one parallel to the axis of a two-stage turbine are shown sideby side following the method used by Moyer. In the figure thepressure is seen to be constant across the sets of vanes, the dropin pressure and consequently the
Size: 1849px × 1351px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1915
