FORMULA OF NPSH available

The NPSH (Net Positive Suction Head) Available or NPSH value of the plant defines the total pressure at the pump suction nozzle for given fluid characteristics at certain flow rate.


This below is formula for find the value of NPSH available. :



1. NPSH A = (P atm - P vp) / rho.g - H static - h loss

for condition of system :

• Open system with water reservoir below pump.
• Unpressurized closed system (condition in daerator of B.F.P system)
• Open system with acetone reservoir above pump, positioned at 900m above sea level

2. NPSH A = (P atm+ P ov - P vp) / rho.g + H static - h loss


for condition of system :

• Closed system with over pressure of propane fluid reservoir above pump, positioned at the sea level.

3. NPSH A = (P atm - P vp) / rho.g + H static - h loss


for condition of system :

• Open system with water reservoir at sea level above pump with different temperature.
  

4. NPSH A = (P abs - P vp) / rho.g - H static - h loss


for condition of system :

• pressurized closed system (condition in daerator B.F.P system).
• Pressurized closed system (gas condition in pressurized vessel).