ABSTRACT
The cavitation surging in a centrifugal pump is a thermodynamic process controlled by hydrodynamic flow patterns. In circumstances where thermodynamic considerations dominate events the phenomenon is described as thermodynamically induced cavitation surging. Thermodynamically induced cavitation surging results from deficiencies in plant design which permit pump operation at zero or near-zero flowrate conditions. The potential consequences of this form of cavitation surging are serious. Breach of the pressure containment boundary may be a possibility; mechanical damage to an axial thrust bearing or to any “less than robust” design of non-return valve is highly likely. In normal service the leak-off system would be expected to open in good time to allow a pressure relieving flow to commence in the leak-off line. The maximum possible pressure rise in the inlet pipe is the difference between the relieving pressure beyond the outlet non-return valve and the pressure at the pump outlet.
