Flow in the Volute of a Centrifugal Pump and Radial Forces on the Impeller

摘要

In a good centrifugal pump the volute is so proportioned that, when the pump works at its normal delivery, the flow out of the impeller into the volute is uniform round its circumference and the static pressure is also fairly constant around the periphery of the impeller. When the pump is operating at a delivery far removed from its normal the outflow from the impeller, even when measured with time-averaging instruments is far from uniform and sometimes considerable changes in static pressure with angular position round the volute are encountered. This non-uniformity of flow and pressure can cause serious radial forces on the impeller which bend the shaft relative to the casing.