A centrifugal pump with backward-curved blades has the following measured performance when tested with water at 20C:

Question:

A centrifugal pump with backward-curved blades has the following measured performance when tested with water at 20°C:
Q, gal/min: 0 400 800 1200 1600 2000 2400
H, ft: 123 115 108 101 93 81 62
P, hp: 30 36 40 44 47 48 46
(a) Estimate the best efficiency point and the maximum efficiency. (b) Estimate the most efficient flow rate, and the resulting head and brake horsepower, if the diameter is doubled and the rotation speed increased by 50%.