The power specific speed of a 4MW Francis turbine is 0.8, and the hydraulic efficiency can be assumed to be 90%. The head of water supplied to the turbine is 100 m. The runner vanes are radial at inlet and their internal diameter is three quarters of the external diameter. The 322 Fluid Mechanics, Thermodynamics of Turbomachinery meridional velocities at runner inlet and outlet are equal to 25 and 30%, respectively, of the spouting velocity.
Determine
(i) the rotational speed and diameter of the runner;
(ii) the flow angles at outlet from the guide vanes and at runner exit;
(iii) the widths of the runner at inlet and at exit.
Blade thickness effects can be neglected