The pump having the characteristics shown in Problem 14.14 was used as a model for a prototype that is to be six times larger. If this prototype operates at 400 rpm, what (a) power; (b) head; and (c) discharge flow rate should be expected at maximum efficiency?

Data From Problem 14.14

Performance curves for an operating centrifugal pump are shown below in both conventional units and in dimensionless form. The pump is used to pump water at maximum efficiency at a head of 90 m. Determine, at these new conditions, (a) the pump speed required and (b) the rate of discharge.

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6. CH 1.00 Efficiency, n 0.75 Cp 3 0.50 0.25 0.04 0.08 0.12 0.16 Co dɔ u 250 100 200 80 Efficiency Power input 150 60 Нead 100 40 360 грm 50 d = 39 cm 0.05 0.10 0.15 0.20 0.25 Discharge, m³/s Head, m; Power, kW 20 Efficiency, %