Pump power curve types

[Oreom]

Hello, I have this pump test results (see attached) which show the pump having a decrease in motor power as the flow increases. The majority of pumps I worked with have always had a linear rise in power as the flow increased, then flatting out. Is the power curve subject to the pump size and type? Thanks for reading through, it would be very helpful if someone could help.

 

[LittleInch]

Looks like an axial pump to me.

Head drops linear from 15m to 4 and reduces faster than the flow increases. Hence power drops as flow increases.

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[Artisi]

"Is the power curve subject to the pump size and type?" what pump size and what type?

Looking very carefully at the crystal ball and reciting a few long forgotten incantations, it would appear the test result shows an axial or extreme mixed flow impeller performance.


It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Oreom]

what pump size and what type

I wish I knew, got that test record from someone who's looking into replacing a pump, still awaiting for a site report. What I was wondering was about was if this kind of power curve is more common with axial pumps?

 

[1gibson]

Size no, type kinda. You'll have a rising power curve with a low specific speed (high head low flow) pump. Near the middle you get pretty flat power curves. Higher specific speed (axial flow) you'll have highest power at shutoff, it decreases from there.

You can calculate the specific speed from the curve using the conditions at the best efficiency point, then start looking for something similar.

 

[LittleInch]

Yes

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Artisi]

Suggest some self-research on pump types/ hydraulics etc- wouldn't go amiss.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)