- 11 8 The Speed Of Rotation Of A Blade Group Of A Reaction Turbine Is 3000 Rev Min The Mean Blade Velocity Is 100 M S 1 (131.37 KiB) Viewed 46 times
11.8. The speed of rotation of a blade group of a reaction turbine is 3000 rev/min. The mean blade velocity is 100 m/s. The blade speed ratio is 0.56 and the exit angle of the blades is 20°. If the mean specific volume of the steam is 0.65 mⓇ/kg, and the mean height of the blades is 25 mm, calculate the mass flow of steam through the turbine. Neglect the effect of blade thickness on the annulus area, and assume 50% reaction blading. (16900 kg/h) 377 397 / 736 Rotodynamic Machinery 11.9 In the blade group of Problem 11.8 there are five pairs of blades. Calculate the useful enthalpy drop required for the group and the diagram power. (117.8 kJ/kg; 553.7 kW) 11.10 Calculate the optimum diagram efficiency for the reaction stage of Problems 11.8 and 11.9, assuming the nozzle angle and the axial velocity remain unchanged, the blade speed being adjusted. Calculate also the blade speed at optimum efficiency. (93.8%; 167.8 m/s) AVISAM