In the water pump of Problem 10.8, the pump casing acts as a diffuser, which converts 60 percent of the absolute velocity head at the impeller outlet to static pressure rise. The head loss through the pump suction and discharge channels is 0.75 times the radial component of velocity head leaving the impeller. Estimate the volume flow rate, head rise, power input, and pump efficiency at the maximum efficiency point. Assume the torque to overcome bearing, seal, and spin losses is 10 percent of the ideal torque at \(Q=0.065 \mathrm{~m}^{3} / \mathrm{s}\).

Data from problem 10.8

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10.8 A centrifugal water pump, with 15-cm-diameter impeller and axial inlet flow, is driven at 1750 rpm. The impeller vanes are back- ward curved (B =65) and have axial width b = 2 cm. For a volume flow rate of 225 m/hr determine the theoretical head rise and power input to the pump.