In a vertical-shaft Francis turbine the available head at the inlet flange of the turbine is 500 ft and the vertical distance between the runner and the tailrace is 6.5 ft. The runner tip speed is 115 ft s, the velocity of the water entering the runner is 130 ft s, and the velocity of the water exiting the runner is constant and equal to 35 ft s. The flow velocity at the exit of the draft tube is 11 5 ft s. The hydraulic energy losses estimated from the turbine are equal to 20 ft at the volute, 3.5 ft at the draft tube, and 33.0 ft at the runner. Determine the pressure head (with respect to the tailrace) at the inlet and exit of the runner, the flow angle at the runner inlet, and the efficiency of the turbine.

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1 2 B Turbine Draft tube (3) HE 4