• # question_answer For maximum blade efficiency of a single-stage impulse turbine, the blade speed ratio, ($\alpha$ is the angle made by absolute velocity at inlet) should be: A) $\cos \,2\alpha$                       B) $\frac{\cos \,2\alpha }{2}$C) $\frac{\cos \alpha }{2}$            D) $\frac{2}{\cos \alpha }$

For maximum blade efficiency of single-stage impulse turbine, blade speed ratio, $\rho =\frac{\cos \alpha }{2}$