Centrifugal pump cavitation specific speed
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Why is it generally required that the cavitation specific speed of centrifugal pumps should not exceed 11,000 USC? What is the reason for this?
Pumps with a high NPSH ratio have low efficiency and a narrow allowable operating range
The cavitation specific speed is a value related to the operational stability of the centrifugal pump impeller; excessive values can lead to vibrations and damage to rotating components.
Does this regulation still apply to axial flow pumps?
This post was last edited by eidl*ang on 2017-1-13 11:47. ? Not applicable; it can be figured out with a simple calculation. The value is very small
Achieving a too high cavitation specific speed is difficult in impeller design; generally, pumps with high requirements for cavitation specific speed are made possible by using methods such as installing an inducer； Also, if the cavitation specific speed is too high, it reduces the efficiency of the pump; unless the physical size of the pump is reduced, this will have a significant impact on its efficiency
Essentially, it is a pump with a high NPSHR; the backflow at the impeller inlet increases, which results in a narrower operating range. Moreover, when the operating point is to the right of the BEP and far from it, the value of NPSHR increases significantly. What the original poster mentioned regarding a value not exceeding 11,000 applies only to hot water or ordinary hydrocarbons; for cold water or standard centrifugal pumps, the value should be no more than 8,500