What is Net Positive Suction Head in pump?

NPSH stands for Net Positive Suction Head and is a measure of the pressure experienced by a fluid on the suction side of a centrifugal pump. NPSH is defined as the total head of fluid at the centre line of the impeller less the fluid’s vapour pressure.

What is the effect of Net Positive Suction Head and cavitation on pump performance?

NPSH or Net Positive Suction Head is a very important part of a pumping system. The systems NPSHA must be higher than the pump’s NPSHR in order for proper pump performance and to eliminate the risk of cavitation, which can damage a pump in short order and shut down operations that depend on that pump.

What is difference between NPSHA and Npshr?

NPSHA is a function of your system and must be calculated, whereas NPSHR is a function of the pump and must be provided by the pump manufacturer. NPSHA MUST be greater than NPSHR for the pump system to operate without cavitating.

How does the net positive suction head prevent cavitation?

To prevent cavitation the pressure reduction in the suction eye must be compared to the vapor pressure entering the pump to determine whether the liquid will vaporize. The amount of excess pressure above the vaporization pressure is called net positive suction head (NPSH).

What does net positive suction head ( NPSH ) mean?

Net Positive Suction Head or NPSH for pumps can be defined as the difference between the suction pressure and the saturation pressure of the fluid, expressed in terms of height of liquid column. NPSH is used to measure how close a fluid is to saturated conditions. Lowering the pressure at the suction side can induce cavitation.

When does cavitation occur in a pump what happens?

Pumps. Listen Now. Pause. Cavitation in pumps is the rapid creation and subsequent collapse of air bubbles in a fluid. When the Net Positive Suction Head Available (NPSHa) is lower than the Net Positive Suction Head Required (NPSHr), cavitation will begin to occur. In many cases, the force of cavitation is strong enough to pit metal components

How does NPSH and cavitation affect the pump?

NPSH AND CAVITATION Liquid vaporization within a pump intake is called “cavitation”. Cavitation reduces a pumps performance and will damage the pump. To understand the occurrence of cavitation, it is important to remember that a liquid will vaporize at a relatively low temperature if its pressure is reduced sufficiently.