An existing Francis radial-flow hydro-turbine is to replace an old hydro-turbine at a hydroelectric dam where...

 

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An existing Francis radial-flow hydro-turbine is to replace an old hydro-turbine at a hydroelectric dam where the design volume flow rate of water is 80 m/s. The inner and outer diameters of the hydro-turbine runner are 2.6 m and 4 m, respectively, while the axial blade widths at the inlet and outlet of the hydro-turbine runner are 0.85 m and 2.1 m, respectively. The hydro-turbine runner blade angles are 71.4 and 15.3 at the inlet and outlet, respectively. The hydro-turbine runner must rotate at 150 rpm to turn the 50 Hz electric generator. Draw a velocity vector diagram for both the inflow and outflow giving the magnitude of all velocity vectors. Calculate the angle through which the wicket gates should turn the water flow (which is measured from the radial direction at the runner inlet), the swirl angle (which is measured from the radial direction at the runner outlet) and hence determine the key (50 marks) performance parameters for the hydro-turbine at this site. An existing Francis radial-flow hydro-turbine is to replace an old hydro-turbine at a hydroelectric dam where the design volume flow rate of water is 80 m/s. The inner and outer diameters of the hydro-turbine runner are 2.6 m and 4 m, respectively, while the axial blade widths at the inlet and outlet of the hydro-turbine runner are 0.85 m and 2.1 m, respectively. The hydro-turbine runner blade angles are 71.4 and 15.3 at the inlet and outlet, respectively. The hydro-turbine runner must rotate at 150 rpm to turn the 50 Hz electric generator. Draw a velocity vector diagram for both the inflow and outflow giving the magnitude of all velocity vectors. Calculate the angle through which the wicket gates should turn the water flow (which is measured from the radial direction at the runner inlet), the swirl angle (which is measured from the radial direction at the runner outlet) and hence determine the key (50 marks) performance parameters for the hydro-turbine at this site.