How does viscosity effect HPSHr?
How does viscosity effect HPSHr?
(OP)
If the NPSHr of a pump is normally measured using water, how does the actual viscosity of the pumped fluid effect the NPSHr? I would have thought that increased fluid velocity would have increased the pressure drop between the pump suction and impellar and as such the NPSHr of a pump would increase with increasing viscosity. I can't find any details of viscosity correction for NPSHr. Anyone able to confirm if NPSHr should be corrected for viscosity.





RE: How does viscosity effect HPSHr?
The total heads and the performance characteristic shown on these curves, apply to media with a density of 1 kg/dm3 and a kinematic viscosity up to 20 mm2/s. If the density is other than 1 the friction must be multiplied by rho.
You can learn a little bit more of viscosity correction on pumps here:
http://www.mcnallyinstitute.com/14-html/14-04.htm
Also, the following link has an excel datasheet that uses the Hydraulic Institute method to predict how a centrifugal pump will perform with higher viscosity fluids:
http://www.chemengsoftware.com/pipesize/pumpds.htm
Hope you find it useful,
EB
RE: How does viscosity effect HPSHr?
EB
RE: How does viscosity effect HPSHr?
The link to the calculator:
http
An explanation of how it works is on:
htt
Hope this helps
Wim