Upsurge and Speed-Rise Charts Due to Pump Shutdown

Radial (centrifugal) pumps can limit and reduce the reverse flow as the pump speeds up in reverse after power shutdown. This may cause head rises at the pump and along the discharge line. Usually the amplitude of these upsurges with either an increase in 2ρ, or with an increase in K(2L/a) for a constant 2ρ, in which 2ρ = the pipeline characteristic parameter; 2L/a = the round trip wave travel time; and K is a pump constant. This paper presents results of an analytical study that show that both the maximum reverse speed rise and the maximum head rise at the pump increase with an increase in K(2L/a) up to some value of K(2L/a) for each 2ρ. However, as K(2L/a) increases beyond this value both the maximum head rise and speed rise decrease. In addition, the effect of friction on head changes in the line is presented. The results are presented in the form of charts that can be used to assist in the design of pump discharge systems.