Industrial Automation & Control challenge
Control loops, interlocks, fail-safe design and functional safety.
Industrial Equipment · Interactive Engineering Model
Pump Power Calculator
Total dynamic head · Friction · Shaft power
Change the operating assumptions and see what actually drives the pump duty — static lift, flow, pipe bore, friction or efficiency. Total dynamic head and shaft power, with friction from Darcy-Weisbach and the friction factor taken from the flow regime rather than assumed.
Duty flow at the operating point, not the peak the line could carry.
Elevation difference between the two liquid surfaces, plus any pressure difference expressed as head. Independent of flow.
Developed length of the line. Add the equivalent length of bends, valves and fittings here — they are not counted separately.
Actual bore, not the nominal size. Friction scales with the fifth power of it, so the difference matters.
Start from an example: 100 m³/h through 250 m of DN150 steel, 25 m lift →
Advanced parameters4
- —Shaft power
- —Total dynamic head
- —Friction head
- —Static share of head
- —Velocity
- —Reynolds number
- —Friction factor
- —Hydraulic power
- —Shaft power
- —Total dynamic head
Move a parameter and the system answers: the velocity in the line, the head the pump must provide, and the power it takes to provide it.
The link carries the figures you entered, in the part of the address that is never sent to a server.
Change one assumption at a time. The model updates from the same calculation used for the reported result.
Try this
Keep flow and static lift fixed. Reduce the pipe bore and watch how much of the total head shifts from elevation to friction.
How the model works
- The liftStatic head is the height the liquid has to gain. It is owed at any flow, and no pipe decision reduces it.
- The lineFriction head is what the pipe takes on the way. It follows the square of velocity, so flow and bore move it hard while length moves it in proportion.
- The dutyThe pump has to provide both. That sum is the total dynamic head, and it is what the curve below is drawn against.
- The powerHydraulic power is flow times head times density; shaft power is that divided by efficiency. The difference is what the machine spends on itself.
Need a model of the actual system, not a single pipe?
We can extend this to the real network — fittings, control valves, parallel pumps and duty variation — and connect it to operating data so the duty point is measured rather than assumed.
Calculation basis 6 steps · view the method →
Velocity = flow ÷ cross-sectional area—Reynolds number = velocity × diameter ÷ kinematic viscosity—Friction factor from Swamee-Jain (or 64/Re when laminar)—Friction head = f × (length ÷ diameter) × velocity² ÷ 2g—Total dynamic head = static head + friction head—Shaft power = density × g × flow × head ÷ efficiency—
Assumptions & limitations Screening estimate for preliminary sizing and system review · 7 assumptions →
This is a screening calculation for a single pipe carrying a Newtonian liquid in steady flow. It excludes fittings, valves and entry losses unless you add their equivalent length, and it does not model NPSH, cavitation, suction conditions, viscosity correction for the pump itself, or the pump's own curve. Select equipment against the manufacturer's curve and a proper hydraulic study, not against this figure.
- Steady, single-phase, incompressible Newtonian flow in one pipe of constant bore.
- Fittings, valves, strainers and entry and exit losses are excluded unless added as equivalent length.
- The Swamee-Jain approximation is used for the friction factor; it sits within about 1% of Colebrook-White over the usual turbulent range.
- Below Reynolds 2300 the laminar value 64/Re is used, and the transition region between 2300 and 4000 is not modelled honestly by either.
- Suction conditions, NPSH available and cavitation are not considered.
- Pump efficiency is taken as a fixed figure, though it varies across the curve; motor, drive and coupling losses are excluded.
- Standard gravity of 9.80665 m/s² is used.
Worked examples
- 100 m³/h through 250 m of DN150 steel, 25 m lift
Open with these figures → - A slow line: 10 m³/h through the same pipe
Open with these figures → - Laminar case: heavy oil at 400 cSt
Open with these figures →
What this model reveals
Pump duty is not one number produced by one cause. Static head comes from the system geometry and remains even at very low flow. Friction is different: it changes rapidly with velocity and pipe bore. This model keeps those contributions separate so you can see which assumption is actually driving the pump requirement.
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