Operation of centrifugal pumps

Abstract

A positive displacement pump delivers at a fixed speed a nearly constant flow rate independently of the back pressure. In contrast, the flow rate of a centrifugal pump depends on the pressure difference Δp = ρ×g×HA imposed by the system on the pump. The pressure rise Δp generally depends on the flow rate because of hydraulic losses. Thus the system characteristic HA = f(Q) is understood as the difference in total pressure which must be supplied by the pump to maintain a specific flow rate through the system, Eq. (T 2.2.6). The operation point of a centrifugal pump is given by the intersection of the characteristics of system asnd pump, Fig. 11.1.