★What is cavitation in pumps:

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Answer 1. The lowest pressure in a pump is found near the inlet of the impeller; when the pressure here drops to the saturated vapor pressure at that temperature, the liquid begins to vaporize, and numerous bubbles escape from the liquid. When the bubbles flow with the liquid to the high-pressure area of the pump, under the effect of external pressure, they suddenly condense back into liquid. At this point, the liquid surrounding the bubble rushes at extremely high speed into the space formerly occupied by the bubble, generating a significant hydraulic shock. Since many bubbles condense per second, many high impact pressures are generated. Under this continuous local impact load, the surfaces of the flow-through components in the pump gradually suffer from fatigue damage, developing many erosive pitting; these pitting then spread in a honeycomb pattern, eventually leading to flaking. In addition to the damage caused by impact, as the liquid vaporizes, the oxygen dissolved in it is released, causing the components exposed to the flow to oxidize and corrode. This phenomenon, in which flowing components are damaged as a result of both mechanical erosion and chemical corrosion, is known as cavitation. Answer 2. At a certain temperature, when the pressure of a liquid is reduced to its vaporization pressure at that temperature, bubbles form in the liquid. This phenomenon of bubble formation is called cavitation. Answer 3. Cavitation occurs when, at a constant pressure on the surface of the tank, the pressure at the center of the impeller drops to equal the saturated vapor pressure of the liquid being transported at that temperature. This causes numerous bubbles to form in the liquid at the inlet of the impeller; as these bubbles move into areas of higher pressure, they are quickly crushed and condensed, creating a vacuum in their vicinity. The liquid particles surrounding them then rush toward the center of these bubbles at high speeds, generating an instantaneous shock pressure. As a result, the impeller is rapidly damaged, accompanied by vibrations in the pump body and noise generation. The pump’s flow rate, head, and efficiency all decrease significantly. This phenomenon is called cavitation. Answer 4: If it is a water pump, the height between the pump and the water surface should be reduced. During operation, a certain amount of air gets mixed into the liquid between the piston and the guide sleeve in the hydraulic cylinder. As the pressure gradually increases, gas in the liquid turns into bubbles. When the pressure reaches a certain limit, these bubbles burst under the high pressure, causing hot and high-pressure gas to be rapidly delivered to the surface of the components. This leads to cavitation in the hydraulic cylinder, resulting in corrosive damage to the components. This phenomenon is known as cavitation.