Negative pressure head

[5303]

Can somebody explain to me what negative pressure head means for a centrifugal pump? I had to design a centrifugal pump to increase the flow rate in a gravity feed slurry line, and ended up with a pump that must develop a total pressure head of -12 m.

 

[aussiemike]

It doesn't sound quite right. Unless there is an error with the negative sign, this implies your pump is acting as a turbine!

It is possible the assumptions you have used in your model don't match reality. Is any part of the pipe flowing part full?

Can you give us a more detailed description of how you came to this conclusion? A description of the system would also help (static elevations, pipe lengths, operating philosophy etc).

Once we do a "quick and dirty" HGL I'm sure it will be crystal clear!

Cheers
Aussie Mike