Pump type selection guide
Compare positive displacement and dynamic pumps by flow, pressure, viscosity, and service conditions.
This guide is prepared for quick engineering review. Critical design decisions still require the relevant standard, supplier data, and engineering approval.
Problem / Objective
Pump selection is more than meeting a target flow rate. Fluid viscosity, pressure loss, cavitation risk, and control method determine the right pump type.
Assumptions
- The fluid is treated as single phase.
- Pipe losses are approximately known.
- Continuous operating point stays near the design point.
Step by step method
- Write the required flow and head.
- Check fluid viscosity and temperature.
- Compare positive displacement and centrifugal options.
- Review cavitation and NPSH margin.
- Choose valve control or speed control strategy.
Common mistakes
- Sizing only for maximum flow.
- Ignoring viscosity impact on motor power.
- Forgetting cavitation risk in the suction line.
Related calculators
Related glossary terms
Quick FAQ
Question: When is a centrifugal pump suitable?
It is usually suitable for low to medium viscosity and variable flow duties.
Question: When should a positive displacement pump be used?
It helps with high viscosity, precise dosing, or high pressure requirements.
Question: How can cavitation be reduced?
Reduce suction losses, increase NPSH margin, and select the correct operating point.
Related engineering links
Calculators, terms, and companion guides that share the same engineering concepts.
Calculators
Fluids & HVAC
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Compute extend/retract force and speed from pressure and flow.
Pipe Pressure Loss
Compute Re, friction factor, and pressure loss via Darcy-Weisbach.
Bending & Deflection
Bending stress and max deflection for a simply supported beam.
Guides
Viscosity classification guide
Practical notes for choosing viscosity without mixing ISO VG, SAE, and lubricant grade systems.
Fluid dynamics basics: pipe and duct flow
A quick guide to laminar flow, turbulent flow, Reynolds number, hydraulic diameter, and pressure loss.
Bolt head types guide
Compare hex, socket head, button head, and countersunk bolts for design, assembly, and service access.
Glossary
Cavitation
Cavitation is a core engineering term. Definition, usage notes, and a practical example.
Reynolds Number
Reynolds Number is a core engineering term. Definition, usage notes, and a practical example.
Viscosity
Viscosity is a core engineering term. Definition, usage notes, and a practical example.
Head Loss
Head Loss is a core engineering term. Definition, usage notes, and a practical example.