Minimum sumergible level - NPSH available
Minimum sumergible level - NPSH available
(OP)
I understand that it should be a minimum sumergible level for vertical pumps to avoid vortix. However how to calculate the NPSH available of the system? Obviusly the static head has to be at least the minimum sumergible level? Any comments?
Thanks a lot
Thanks a lot





RE: Minimum sumergible level - NPSH available
NPSHa should be calculated from that same minimum liquid level to the pump centerline.
http://virtualpipeline.spaces.msn.com
RE: Minimum sumergible level - NPSH available
By definition, NPSH is the net positive suction head above the vapor pressure of the liquid at the suction flange of the pump top maintain a liquid state.
You can use NPSHa = Hp +/- Hs - Hf - Hvp
Basi8cally NPSH = static suction head (if any)+ atmospheric pressure (if open tank) or the psitive pressure (if closed pressurized tank) which is Hp above. Then subtract the vapor pressure (Hvp), friction losses (Hf) and static suction lift (Hs).
The NPSHa is directly dependent on the suction conditions and in turn defines the required suction characteristics of the pump. You haven't provided any detaiuls, but when you consider a typical application of NPSH as it affects the system, the keys are head-capacity and pump suction size.
Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com
RE: Minimum sumergible level - NPSH available
RE: Minimum sumergible level - NPSH available
Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com
RE: Minimum sumergible level - NPSH available
http://virtualpipeline.spaces.msn.com
RE: Minimum sumergible level - NPSH available
RE: Minimum sumergible level - NPSH available
asked a number of NPSH questions just a couple of days
ago.
http://virtualpipeline.spaces.msn.com