The performance curve of a pump at 2000 rpm is well represented by the quadratic equation: where H (m) is the total head and, Q (Lsí1 ) is the flow rate. Two such pumps, installed in parallel,...

The performance curve of a pump at 2000 rpm is well represented by the quadratic equation:

where H (m) is the total head and, Q (Lsí1 ) is the flow rate. Two such pumps, installed in parallel, circulate water through a closed pipe network as depicted in Fig. E12.11.1. The system curve for the pipe network has been obtained as

where H is the head loss in m, and Q is the water flow rate in m3 s í1 . (i) Determine the flow rate when both pumps are running, and the ideal power input to the pumps. (ii) If one of the pumps is switched off, determine the flow rate through the pipe network, and the power input.