NPSH
（重定向自Net positive suction head）
![A simple hydraulic pumping circuit. Point 0 is the free suction surface, and point i is the inlet of the impeller.](/Images/godic/202501/29/Simple_pump_schematic.svg4321.png")
In a hydraulic circuit, net positive suction head (NPSH) may refer to one of two quantities in the analysis of cavitation:
NPSH is particularly relevant inside centrifugal pumps and turbines, which are parts of a hydraulic system that are most vulnerable to cavitation. If cavitation occurs, the drag coefficient of the impeller vanes will increase drastically - possibly stopping flow altogether - and prolonged exposure will damage the impeller.