Avoiding cavitation in the suction stage of high-energy pumps

How susceptible a high-energy pump∗ will be to cavitation behaviour and hydraulically induced forces, and what effects these forces will have on pump operation and longevity can be defined by the relationship of impeller stage pressure rise (ΔP), specific speed (Ns) and inlet tip speed (Ue). As well as the usual problem of reduced head generation the adverse effects of cavitation in high-energy pumps are suction impeller erosion and system instability. System instability, caused by the introduction of a compressible volume (the cavitation vapour itself) into the essentially incompressible pump system, can lead to pressure pulsations, varying flow delivery, and piping or pump vibration. The ultimate solution to both problems is the removal of the vapour (or cavitation) from the system.