Question

A reaction turbine has drum diameter of 2.15 m at a speed of 750 rpm with 14.5 kg/s of steam consumption. The height of the blade at a certain location is 0.16 m while the discharging angle is 25. The pressure at this place is 4 bar and dryness fraction is 0.97. Estimate the power developed in the particular ring by assuming the turbine efficiency of 75%. Also find the heat drop while the steam passing over the pair of

Answer 1

Dum diameter, D = 2.15m speed, N = 750pm mass of steam, m = 14.5rpm blade height, h = 0.16m doyness frection, x = 0.97 discharge angle, alpha = 25 degree turbine efficiency, eta_T = 75%= 0.75 blade speed u = pi(0 + h)N/60 = pi(2.15 + 1.06)times 750/60 = 90.713m/s for reaction turbine v_1 = v_r_2 and v_2 = v_r_1 assume speed ratio, e = u/v_1 = 0.75 v_1 = 90.713/0.75 = 120.951m/s v_w_1 = 115m/s, v_w_2 = 20m/s v_f_1 = v_f_2 = 25m/s from steam tables at l bar specific volume, v_g = 0.462m^3/kg specific volume of steam, v_s = x times v_g v_s = 0.97 times 0.462 = 0.448m^3/kg m_g = pi(D + h)h.v_f_1/v_s = pi(2.15 + 0.16) times 0.16 times 25/0.448 = 64.795 kg/s power developed p_f = m_s times (j_omega + j_omega) times v/1000 = 64.795 times (115 + 20)times 90.713/1000 p_f = 793.496kw