How do centrifugal pumps resist cavitation?

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As is well known, when there is air inside the centrifugal pump casing, the lower density of air compared to that of the liquid results in a smaller centrifugal force. As a result, the pressure difference between the surface of the liquid in the tank and the pump’s suction inlet is not sufficient to force the liquid in the tank into the pump; in other words, the centrifugal pump does not have self-priming capability, which prevents it from pumping liquid. This phenomenon is known as \"cavitation\". So, how can we improve the cavitation resistance of centrifugal pumps? What are the tricks? Tricks for enhancing the cavitation resistance of centrifugal pumps themselves: (1) Improve the structural design from the pump’s suction inlet to the vicinity of the impeller. Increase the flow area; increase the radius of curvature at the inlet section of the impeller cover to reduce the sudden acceleration and pressure drop of the fluid flow; appropriately reduce the thickness at the blade inlet and round it out to make it more streamlined, which can also reduce the acceleration and pressure drop around the blade tip; improve the surface finish of the impeller and the blade inlet areas to minimize frictional losses; extend the edge of the blade inlet toward the impeller inlet so that the fluid flow can be acted upon earlier, thereby increasing pressure. (2) A pre-induction wheel is used to enable the liquid flow to do work in advance within the pre-induction wheel, thereby increasing the pressure of the liquid flow. (3) A double-suction impeller is used, allowing the fluid to enter the impeller from both sides; as a result, the inlet area doubles, and the inlet flow velocity can be reduced by half. (4) A slightly larger positive attack angle is adopted in the design conditions to increase the blade inlet angle, reduce bending at the blade inlet, and minimize blade blockage thereby increasing the inlet area; this improves the operating conditions under high flow rates and reduces flow losses. However, the impact angle should not be too large, otherwise it will affect efficiency. (5) Use materials resistant to cavitation. Practice has shown that the higher the strength, hardness, and toughness of a material, as well as its chemical stability, the better its resistance to cavitation