In a fully low-pressure oxygen concentrator, cavitation of a centrifugal liquid oxygen pump is a process of damage to the pump.
When a centrifugal pump is running, the pressure inside the impeller is different. The pressure at the inlet is lower, and the pressure at the outlet is higher. The gasification temperature of the liquid is related to the pressure. If the temperature of the liquid entering the pump is higher than the gasification temperature corresponding to the inlet pressure, some liquid will produce gasification and form bubbles. When bubbles are carried by liquids to areas with high pressure, due to the corresponding increase in gasification temperature, the vapor will condense back into a liquid, and the bubbles will quickly rupture. At this point, due to the difference in density between gas and liquid by several hundred times, at the moment when the bubble condenses and suddenly shrinks in volume, the surrounding liquid rushes towards the space occupied by the bubble at a high speed, exerting a violent impact inside the liquid. If this phenomenon occurs on the surface of the blade, the metal material will be eroded due to repeated high impact stresses. It is called "cavitation".
When cavitation occurs, the outlet pressure fluctuates violently, the continuity of flow is disrupted, and the pump flow rate drops sharply. In severe cases, it is often accompanied by gas blockage, causing serious damage to the pump.
