- 11 5 The First Stage Of A Turbine Is A Two Row Velocity Compounded Wheel Steam At 40 Bar And 400 C Is Expanded In The N 1 (82.3 KiB) Viewed 45 times
11.5 The first stage of a turbine is a two-row velocity compounded wheel. Steam at 40 bar and 400°C is expanded in the nozzles to 15 bar, and has a velocity at discharge of 700 m/s. The inlet velocity to the stage is negligible. The relevant exit angles are: nozzle 18°; first row blades 21°; fixed blades 26.5°; second row blades 35º. Take the blade velocity coefficient for all blades as 0.9. The mean diameter of the blading is 750 mm and the turbine shaft speed is 3000 rev/min. Draw the velocity diagram for this wheel and calculate: (i) the diagram efficiency; (ii) the stage efficiency. (70.8%; 67.4%)