How To Prevent And Reduce Cavitation Of Water Pumps

Nov 03, 2025

 

Ⅰ, Improve the anti cavitation performance of water pumps

1. Reduce the necessary cavitation allowance

(1) Water pump with double suction impeller. Due to the smaller cavitation allowance of double suction pumps compared to single-stage single suction pumps, double suction impellers should be used as much as possible for pumps with the same speed and flow rate.
(2) Appropriately increase the diameter of the impeller inlet and the width of the blade inlet. When the inlet diameter of the impeller and the inlet width of the blades increase, the inlet velocity and relative velocity of the impeller decrease, indicating a decrease in the critical cavitation allowance of the pump. But at this time, the area of the leakage reducing ring at the inlet of the impeller increases, the leakage volume increases, and the volumetric efficiency of the pump will decrease.

 

(3) Install an inducer in front of the impeller. Install an inducer in front of the impeller of the centrifugal pump. The induced impeller and pump blades rotate, and the pressure wheel generated by them is assembled coaxially and runs together. The pressure generated by them increases the pressure at the impeller inlet, improving the pump's anti cavitation performance. However, adding inducers will make the performance of the water pump unstable, so further exploration and research are needed.

2. Improve the anti cavitation ability of overcurrent component materials

In order to reduce the damage of cavitation to the overcurrent components of water pumps and extend their service life, materials with strong anti cavitation performance are often selected. If materials such as cast manganese, bronze, stainless steel, and alloy steel are used to cast impellers; Alternatively, polymer coating or laser spraying can be used to coat the surface of overcurrent components to resist cavitation damage. In addition, precision machining the surface of overcurrent components to improve their smoothness can also reduce the harm of cavitation.

 

Ⅱ, Improve the anti cavitation ability of the water inlet device

The cavitation allowance is closely related to the inlet device and pipeline system, so a well-designed inlet device should be used to maximize the cavitation allowance at the pump inlet to meet the requirements of dynamic pressure drop inside the pump.

1.  Reasonably determine the suction height of the water pump

 

Due to the fact that water pumps generally operate under non design conditions, various working conditions that may be encountered during pump operation should be fully considered, and the determined suction height should meet the requirements of water pump suction performance under any working condition.

2. Choose a reasonable inlet pipe 

 

 

Minimize the length of the inlet pipe and unnecessary pipe accessories as much as possible, increase the inlet pipe diameter appropriately to reduce hydraulic losses in the inlet pipe, and increase the cavitation allowance at the pump inlet. For high flow pumps, distributing the water flow velocity and pressure in the inlet pipeline as evenly as possible will help prevent cavitation.

3. A well-designed inlet pool

 

A good inlet pool can not only reduce the drop of water level in the pool and decrease the resistance coefficient of the inlet pipe, but also ensure a stable water surface without generating vortices. It can prevent air from entering the pump and prevent premature cavitation.

Ⅲ. Measures that can be taken in operational management

1. Try to ensure that the water pump operates within the designed operating conditions 

 

According to the specific conditions of the pump station, adjustment measures such as variable valve, variable speed, and variable angle can be adopted to prevent the operating conditions of the water pump from deviating too far from the design conditions.
 

2. Control the amplitude of the actual speed of the water pump being higher than the design speed

 

Due to the fact that the required cavitation allowance is proportional to the square of the rotational speed, when the rotational speed is too high, not only does it significantly increase the required cavitation allowance, but it also reduces the effective cavitation allowance.

 

 

3. Fill with a small amount of air or high-pressure water flow

 

When cavitation occurs during the operation of the water pump, a small amount of air or high-pressure water flow can be filled into the inlet of the water pump to reduce or avoid cavitation hazards.