Dear sea friends, how should we understand this concept of NPSH regarding centrifugal pumps?

What does NPSH mean for centrifugal pumps? (China Pump Valve Network) NPSH is the abbreviation for Net Positive Suction Head; literally translated as net positive suction head, it is commonly referred to as cavitation head in China. It denotes the energy that the liquid at the inlet of the impeller (relative to a reference level) possesses, above the saturated vapor pressure of the liquid at that temperature. It is determined by the pump installation conditions. Expressed in head form. The unit is m. 　　For a given pump, the required (NPSH) value at a specified speed and flow rate is determined during its design and manufacturing; it is referred to as the required net positive suction head (NPSH) r, measured in meters. 　　At a given flow rate or head, the (NPSH) value at which cavitation just occurs inside the first-stage impeller is called the critical net positive suction head, (NPSH)c, measured in meters. NPSHa, also known as effective net positive suction head or available net positive suction head, is expressed in meters as well. For information on the relationships between these parameters, please refer to: http://www.songlone.com/t_9.html. The safety margin related to NPSH is given by NPSH margin = NPSHa – NPSHr. To understand this better, you can also read the posts on this forum: For posts 2 and 3: Understanding the definitions of NPSHr and NPSHa – Powered by Discuz! http://bbs.hcbbs.com/thread-912425-1-1.html; for post 14: I would like to ask everyone which domestic manufacturers can produce this type of pump... – Powered by Discuz! http://bbs.hcbbs.com/thread-928345-1-1.html. It’s recommended that you ask more specific questions; in fact, once one particular concept is understood, everything else will become clear as well.: victory: