Velocity profile at the throat of a centrifugal pump

[MotorPump]

What will be the best assumption for the tangential velocity profile of the flow at the throat of (simple, single volute) centrifugal pumps?

I'm trying to approximately calculate the crude formula for the amount of flow throught the throat in a centrifugal pump.

I expect the formula may turn out as a function of rotational velocity of impeller, flow rate through impeller, area of the throat, etc.

Would couette flow assumption work?

Is there conventional assumption for the flow at the throat?

Please let me know the good source of references for this kind of problem.

Thank you in advance.

 

[checman]

MotorPump On a pump with a mechanical seal it is normally governed by the clearance between the shaft sleeve and the throat along with the differential pressure across the throat. Several things may influence the pressure behind the impeller. Are there balance holes or pump out vanes on the impeller? As far as flow through the throat it is normally determined by the flush or suck back piping arrangement to the stuffing box or seal chamber. If there is no flush the box is referred to as dead ended. The box is at the same pressure as the liquid behind the impeller. No differential pressure, no measurable flow for all practical purpose. Unless this is a packed pump then the flow would be determined by the gland leakage. Flowserve sealing division has a good program to determine flow through throat bushings.

Regards Checman