Reading Pump Curve for Fluid Which is Not Water 2

[365che]

All,

Does the total dynamic head get divided by the SG prior to plotting onto the pump curve for a fluid that is not water?

If I remember correctly, pump curves are drawn based of the assumption of water.

 

[Rputvin]

If you have additional fluid properties you can plug in a custom fluid in most of the sizers.

Increased SG results in a higher discharge pressure

Here are two curves for the same pump, targeting 100gpm/60psi design point, one run with water, one run with 1.3 SG.

Edit: hard to read as posted, but the impeller trim line is about 20psi higher, and max shutoff pressure is 90-95psi on the pump with water, 120 at 1.3SG. You also jump up a motor size on this pump going to higher SG

 

[1503-44]

Proper pump curves show head, not pressure. The reason for that is that pump head does not change regardless of the fluid being pumped. It remains constant for any fluid. If you want to know the pressure corresponding to a given fluid at a specific head, then you must multiply head x fluid density.

For certain fluids, esp those with unusual viscosities, a pump will not develop the same head as water. In those cases you should consult the mfgr, or otherwise make proper compensation.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[pierreick]

HI,
I think you need to review the basics about centrifugal pump . Consider to read the paper attached .
Good luck
Pierre

 

[365che]

Update:

My question was silly. The total dynamic head I calculated should have been calculated in a way which included the S.G in the first place. I.E when converting from psi to head for each component, I should have used S.G which I did not do for some of the suction head terms. I've corrected my mistake and arrived at a final head that lands perfectly on the curve at the expected location.

The modification I intend to perform to the system will minimally effect the flow as predicted by the pump curve shift when adding the anticipated pressure drop.

Thanks