What is pump specific speed?

Ns = N × √Q / H^(3/4), where N is rotational speed (rpm), Q is flow rate (gpm or m³/s), and H is total head (ft or m). Low Ns (500–1000) indicates radial flow centrifugal pumps; high Ns (10,000+) indicates axial flow propeller pumps.

Why is specific speed important in pump selection?

Specific speed determines the most efficient impeller type. Radial impellers suit low flow/high head applications; mixed-flow impellers suit moderate conditions; axial impellers suit high flow/low head. Matching pump Ns to system requirements maximizes efficiency (per Hydraulic Institute ANSI/HI 1.1-1.5).

Pump Specific Speed (Ns) Calculator

Calculate dimensionless specific speed to classify pump type and select the optimal impeller geometry for hydraulic applications.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Calculate dimensionless specific speed to classify pump type and select the optimal impeller geometry for hydraulic applications. Use the pump specific speed result to inform your clinical assessment.

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Pump Specific Speed (Ns) Calculator

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Frequently Asked Questions

What is pump specific speed?

Why is specific speed important in pump selection?