Relationship between centrifugal pump impeller size and required net positive suction head
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Dear sea friends, does a larger impeller necessarily require a smaller net positive suction head? Or some other kind of relationship
For pumps of the same specification, at the same flow rate, a pump with a larger impeller diameter must have a smaller net positive suction head
Centrifugal pumps follow a law regarding the impeller: the flow rate is proportional to the diameter of the impeller. In other words, the range of flow rates that can be pumped by impellers of different diameters varies. At low flow rates, the NPSH requirements for these two types of impellers differ little; however, when an impeller with a smaller diameter handles a higher flow rate (while an impeller with a larger diameter may be at its optimal efficiency point), the difference in their NPSH requirements becomes significant.
You can take a look at the image; if the flow rate is 6 cubic units, there is a significant difference in the net positive suction head between impellers with a diameter of 130 mm and those with a diameter of 209 mm
Thank you, I understand a lot more now. I’ll read the book again to learn more*