VALICALC · ENGINEERING WORKFLOW
Pump system head and power check
Combine pipe/fitting loss, elevation and boundary pressure into total dynamic head, then estimate hydraulic, shaft and electrical power.
Start this workflowWhat do I need to know first?
- Design flow, liquid density/viscosity and actual pipe bore
- Pipe lengths, fittings and elevation difference
- Boundary pressures and realistic pump/motor efficiencies
Goal and model boundaries
Document a system operating-point estimate and its power requirement before comparing a manufacturer pump curve.
- The operating flow is an input; this is not an automatic intersection with a manufacturer pump curve.
- NPSH, cavitation, suction arrangements and transient behavior are outside this sequence.
Establish the friction basis
Verify bore, pipe material and losses at the design flow.
Darcy pressure loss includes straight pipe and the entered ΣK.
- Expected output
- A friction/head-loss basis at the chosen flow.
- Next step
- Carry the same bore and fluid conditions to TDH; do not add the same loss twice.
Build total dynamic head
Enter elevations, boundary pressures, pipe geometry and fitting losses.
The TDH tool combines static/boundary terms and its calculated system losses.
- Expected output
- Total head at the supplied operating flow.
- Next step
- Use the resulting TDH once in the power calculation.
Estimate the power chain
Use the same Q, TDH and liquid density; enter efficiency assumptions.
Phyd = ρgQH; Pshaft = Phyd/ηpump; Pelec = Pshaft/ηmotor.
- Expected output
- Hydraulic, shaft and electrical powers.
- Next step
- Compare flow/head against a manufacturer curve and review suction/NPSH separately.
Units and context
- Head in metres or feet represents energy per unit weight; pressure depends on fluid density.
- Enter pump and motor efficiencies separately; neither is a universal constant.
Common mistakes to avoid
- Using only elevation as TDH
- Adding pressure in kPa directly to head in metres
- Treating hydraulic power as electrical input power