What is the Efficiency of a Centrifugal Pump Used as a Turbine?

[iajaia]

Centrifugal pump as turbine!

Dear Friends,

Francis turbine and centrifugal pump has got the same (reverse ofcourse) technologies rt. Have they both got the same manufacturing criterion? will centrifugal pumb, if used as a turbine, have the same efficiency as that of francis turbine?

 

[Pkruse]

It is common in fluid power to use the same device as either a pump or a motor, sometimes alternately so in the same system. There would be some difference in efficiency depending on if the device was primarily designed as a pump or a motor, and upon how closely it is operating to its design point. It is possible to be more efficient as a pump at one design point and as a motor at another design point

 

[iajaia]

So, how to select a centrifugal pump to be used as a turbine to get the best efficiency.
From the pump curves how can we find that?
Say if the operating conditions are, 10 mtr head and discharge of 1 m3/sec.

 

[Pkruse]

I would contact the engineering department of the pump manufacturer. I've never seen enough information in the published data to figure that out. In some cases you will have to depend upon his intuitive opinion based upon his experience under similar conditions.

 

[256bits]

Someone has already studied and published in 1977 US Dept of the Interior
http://www.usbr.gov/pmts/hydraulics_lab/pubs/EM/EM39.pdf
A good friday night read - lots of graphs

although I do not know if optimization is reached for either turbine/pump mode in relation to what pkruse stated.