1. Inlet Pool

At the operating site, it is both essential and straightforward to inspect the flow conditions in the suction basin when cavitation (or other malfunctions) occur in a pump. If strong vortices are visible on the basin surface, consider installing a vortex breaker. In addition, the geometric dimensions of the pipe inlet relative to the suction basin should be carefully evaluated—for example, whether the distance between the pipe inlet and the basin wall is appropriate and whether air bubbles are entering the pump suction line. It is also crucial to monitor the water level in the basin; raising the suction-basin water level can mitigate or even completely prevent cavitation.

2. Inlet Piping

In addition to minimizing pipeline losses—such as by using as few bends and unnecessary valves as possible—the inlet piping should be designed so that no section rises above the pump inlet, thereby preventing air from accumulating within the pipe.

3. Adjust pump flow

When there is a certain discrepancy between the pump design selection and actual operating conditions, cavitation and suboptimal economic operation can be addressed by trimming the impeller, with the aim of eliminating cavitation and achieving efficient operation. Practical experience has demonstrated that this approach is indeed effective.

4. Utilizing an ejector structure

In principle, the jet device functions as a liquid–liquid ejector pump. A high-pressure water stream is drawn from the pump outlet and directed into the high-pressure chamber shown in the figure; this high-pressure water then enters the pump’s suction pipe through an annular nozzle. The high-pressure water mixes with the water in the suction pipe and exchanges energy with it, resulting in an increase in the total energy of the mixed fluid compared with that of the original suction-water flow. This increased energy level ensures that the required net positive suction head at the pump inlet is met.

5. Imported gas supplementation

Air injection does not prevent cavitation from occurring, but when applied appropriately it can mitigate the damage to the flow passage walls caused by cavitation bubble collapse, acting like a protective sponge layer that shields the wall surfaces. This approach is widely used in hydraulic turbines and other similar applications; however, air injection into pumps is rarely employed due to the difficulty of accurately controlling the injection rate.
Air injection for the prevention and control of pump cavitation is a highly technical process; only when the air-injection flow rate, location, and method are properly optimized can satisfactory results be achieved. Otherwise, the pump’s flow rate, head, and efficiency will decline significantly, leading to adverse consequences.