Ok I think I finally get it. NSPHr marks the point when the inlet pressure gets low enough relative to the vapor pressure to cause about a 3% decrease in pump TDH. Cavitation had started at something slightly higher than NPSHr. So basically, you want to stay above NPSHr by a reasonable amount...
Thank you I understand now. I had totally forgotten that there is some space between the inlet of the pump (where the gauge is) and the eye of the impeller, hence there is a pressure drop from the inlet to the impeller. So since we can't really measure the pressure directly at the impeller, we...
Hello, this is my first time posting here. I hope this doesn't come off as a dumb question but here goes:
Premise
1.) NPSHa is the difference between stagnation pressure at the pump inlet, minus the vapor pressure associated with the temperature at the inlet.
NPSHa = Pstagnation - Pvapor
2.)...
