Regarding the issue of cavitation
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This post was last edited by qazxsw119 on 2010-1-11 08:16. If cavitation occurs in a centrifugal pump, which component is more severely affected: the impeller or the volute? At what percentage of the rated flow rate does a centrifugal pump experience cavitation?
It should have a more severe impact on the impeller of the centrifugal pump. The cause of cavitation has little to do with the pump’s flow rate. When the pressure at the pump inlet is lower than the saturated vapor pressure of the material at that temperature, bubbles form within the material. As the pump’s impeller rotates and the pressure increases to a level higher than the saturated vapor pressure of the material at that temperature, the gas phase liquefies, and the liquid droplets rapidly fill in the spaces occupied by those bubbles, resulting in honeycomb-shaped depressions on the surface where the pump comes into contact with the material.
Is what the poster is trying to say is that low flow rates lead to more turbulent circulation of the medium inside the pump, which causes the temperature of the medium to rise and results in cavitation? This shouldn’t be the main cause of cavitation
This post was last edited by cnoocjeff on 2010-1-10 at 14:45. Centrifugal pumps generally have a minimum flow rate limit for continuous operation; it is not allowed to operate continuously at a flow rate lower than this value. The main reason for this is to prevent vaporization of the fluid and resulting cavitation. If operational conditions require operation at the minimum continuous flow rate, then it should be taken into account during the design phase by including a minimum return line (which usually leads back to the inlet buffer area). Otherwise, there may be an issue with the pump selection
When cavitation occurs, it is the pump casing that suffers the most damage; the area where cavitation takes place is in the high-pressure zone, near the pump outlet. I’m not sure if this understanding is correct. According to the practical experience of some friends, the cavitation occurs on the back side of the impeller, which is also a high-pressure area
What percentage of the rated flow rate should the pump generally operate at?
Based on experience, it should have a greater impact on the impeller