Can I model PD Pumps?

Yes. The software is provided with a library of PD Pumps and Rotating PD Pumps. Engineers can expand the library by adding new pump models as and when required. It should be noted that, when adding a new pump to the database, you are only required to do so once. The pump will then be stored in the database and shall be available for all future design/modeling projects.

When defining a PD Pump in the database, you are required to enter "Yes" or "No" for the row titled "Use Internal Eff. Correction".


- Choosing "No" requires the user to define the curve relationship for "Performance Factor" (this is a performance degradation factor).


- Choosing "Yes" allows FluidFlow to automatically apply a correction factor for pump efficiency.


The "Performance Factor" represents the performance degradation factor which is a function of pump speed and typically has a range of 0 - 1. The degradation factor takes into account the pump slippage and performance "tail-off" with changes in pump speed.


A major effect on PD pump performance is the loss of flow due to slip conditions. The expanding cavity on the inlet side of a PD pump creates a low pressure area that requires to be filled with fluid. This cavity can then be filled with fluid from the inlet pipeline under ideal operating conditions. However, if slip occurs, the cavity may also be partly filled with fluid on the discharge side flowing back through the pump clearances to the inlet side, thus affecting the overall pump performance. In general, the pump performance is dependent on the slip which occurs in a pump.