performance curve

[nileng]

Hi

I want to modify a pump charactristic curve which is gained from the experimental test.the head at shutoff is higher than the desired curve (required curve)but at bep and over bep flows the head is smaller.and the curve is steep. what shall I do in order to increase the head at BEP and at overload. and also I want to increase of efficiency?

 

[nileng]

Thanks, does underfiling makes the performance better? according to standard Z138 what kind of under-filing is suitable? b=(1/2)U, 1/3(U),OR (2/3)U? (U= width of vane trailing edge before machining, b= width of vane trailing edge after machining)

 

[Artisi]

Without prior experience with your particular impeller, I would suggest it's trail and error at this stage.

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.)