So am I correct here...
If you have a liquid (SG = 1, VP = 0 psia, and no friction loss in the pipe for simplicity) column that is 2.31 feet high....
NPSHa at the bottom of that column is: NPSHa = 2.31 ft (liquid height) + 33.957 ft (atm pressure in ft) - 0 (line loss) - 0 (vapor pressure) =...
micalbrch,
So, here's my thought process on why I'm thinking that. Please correct me if I'm wrong anywhere.
NPSH is the head required to prevent cavitation right?
With the fluid's specific gravity, that head can be converted to a pressure. This pressure is the pressure required to keep that...
BigInch,
That all makes absolute sense.
So what is the advantage of using absolute pressure? You say it eases the understanding, but it always seems easier to me to think in terms of gauge pressure. Maybe because like you and GHartmann stated, most NPSHr values are given in terms of absolute...
GHartmann,
So you're saying most NPSHr values on a pump curve are given in absolute feet of head. How can you tell? Is it just accepted to be absolute head? The reason I'm asking is that I don't think I've ever seen that specifically called out on a pump curve (it just says ft).
Also, that...
micalbrch,
Yes that value was received by the supplier. And I'm assuming an NPSHr value of 9 psia (~ -5.7 psig) means this pump can pump the specified fluid even under partial vacuum at the suction without cavitating? It would make sense to me because it's a positive displacement pump.
First off this may be a stupid question but I cant seem to figure this out from any online sources. I'm pretty new (currently interning) but I feel like I have a pretty good grasp of NPSHa/NPSHr and how to calculate them until my mentor ran across this diaphragm pump that he says was incorrectly...
