从式(1- 62)可以看出,当转速增大1倍时,泵所必需的汽蚀余量增大3倍，渣浆泵的抗汽蚀性能急剧下降，因此，若用增加转速的方法来提高泵的单级扬程，必须考虑泵的抗汽蚀性能。高速泵一般装有前置诱导轮 ,就是解决此矛盾的一种方法。
Cavitation similarity law and specific speed of slurry pump
In the design and use of centrifugal pumps, for pumps with similar geometry, in addition to the similarity between flow, head and power, the similarity between cavitation performance should also be considered. The similarity law of cavitation and specific speed of cavitation are used to correlate the cavitation performance and design parameters of the pump. The specific speed of cavitation can reflect the anti cavitation performance of this series of pumps.
1. Cavitation similarity law
The ratio of NPSH required for model pump and prototype pump is:
For the same pump (d '= D), when the speed changes, the necessary NPSH of the pump is calculated according to formula (1-62):
From formula (1-62), it can be seen that when the speed is doubled, the necessary NPSH of the pump increases by three times, and the anti cavitation performance of the slurry pump drops sharply。 Therefore, if the speed is increased to improve the single-stage head of the pump, the anti cavitation performance of the pump must be considered。 The high-speed pump is generally equipped with a front inducer, which is a way to solve this contradiction。