a. A 6-inch diameter impeller in a pump is operating at peak efficiency and rotating at 3500 rpm. What is the expected flowrate, Q, and head available, h_a, if the speed of this same pump is reduced to 2800 rpm while operating at peak efficiency?

b. If the pump impeller is increased from 6-inch to 8-inch diameter and continues to operate at a speed of 3500 rpm, what is the expected flowrate, Q, and head available, h_a?

50% 500 8 in. dia 63 65 4007 65 63 60 300 55 6 Head (ft) -40 bhp 200 50 30 15 100 25 20 15 NPSHR - 10 5 207 OUT NPSHR (ft) - ! 1 1 1 1 1 - - 0 40 80 120 160 200 240 280 320 Capacity (gal/min)