1. Cavitation
At a certain temperature, when the pressure is reduced to the vaporization pressure at that temperature, the liquid will generate bubbles. This phenomenon of generating bubbles is called cavitation.
2. Cavitation collapse
When the bubbles generated during cavitation flow to high pressure, the volume of the bubbles decreases and they are destroyed. This phenomenon of bubbles disappearing into the liquid due to pressure rise is called cavitation collapse.
3. The causes and hazards of cavitation
When the pump is in operation, if the partial area of its overflow part (usually somewhere behind the impeller blade inlet) is for some reason, when the absolute pressure of the pumped liquid drops to the vaporization pressure of the liquid at the current temperature, the liquid will be in the At the beginning, it began to vaporize, generating a large amount of steam and forming bubbles. When the liquid containing a large number of bubbles passed through the high-pressure area in the impeller, the high-pressure liquid around the bubbles caused the bubbles to shrink sharply and burst. While the bubbles are condensing and breaking, the liquid particles fill the cavities at a very high speed, generating a strong water hammer effect at this instant, and striking the metal surface with a high impact frequency. The impact stress can reach hundreds to thousands of atmospheres. The impact frequency can reach tens of thousands of times per second. In severe cases, the wall thickness will break down.
4. Cavitation process
The process of generating bubbles and bursting bubbles in the water pump and damaging the overcurrent parts is the cavitation process in the water pump. In addition to damaging the flow parts, the pump will cause noise and vibration after the cavitation, and the performance of the pump will be reduced. In severe cases, the liquid in the pump will be interrupted and cannot work normally.
