Positive-Displacement Pumps: Modeling Fixed Flow and Discharge Pressure
Engineering context
A PD pump delivers an essentially fixed volumetric flow per revolution, largely independent of discharge pressure. The system resistance does not set the flow: it sets the pressure the pump must develop to push that fixed flow through the route.
Booster pumps add head in series with an existing driver to reach a higher operating pressure or recover head lost along a long route.
Start with guided FluidFlow training
Free TrainingEngineering workflow
- Decide: fixed-displacement source (PD pump) or curve-following machine in series (centrifugal booster).
- For a PD pump, pick the component that matches your data: Positive Displacement Pump or Compressor when sizing off vendor performance-factor data (covers most piston, diaphragm, gear, and lobe pumps); Rotating Positive Displacement Pump only when you have slip-capacity-vs-viscosity data (e.g., screw pumps).
- Lay out the route and assign pipe, fitting, and fluid data.
- For a booster, add a second pump component in series and define its performance curve.
- Set boundary conditions at supply and delivery ends.
- Solve and read developed pressure, velocities, and power (PD) or combined operating point (booster).
- Check discharge pressure against equipment and pipe ratings.
How FluidFlow helps
Positive Displacement Pump or Compressor and Rotating Positive Displacement Pump components both represent the fixed-flow machine — pick the one matching your available vendor data. Route resistance and fluid properties solve together, so you see developed pressure and power directly.