Fluid Pipe Network & Pump Sizing Lab
Size a pipe run and a centrifugal pump, watch water flow through the pipe live, and see exactly where the pump curve and system curve meet to set the real operating flow and head.
Change the pipe length and diameter, static lift and pump curve, and watch water flow through the pipe while the pump curve and system curve find their operating point.
hf = f·(L/D)·(V²/2g), V = Q/A, f from Swamee–Jain, operating point where Hpump(Q) = Hstatic + hf(Q)About the Fluid Pipe Network & Pump Sizing Lab
Free fluid pipe network & pump sizing lab. Size a pipe run and a centrifugal pump, watch water flow through the pipe live, and see exactly where the pump curve and system curve meet to set the real operating flow and head. Drag, change the sliders and see the result live. No sign-up, works on phone and computer. Built for engineering, the fluid pipe network & pump sizing lab runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Size a pipe run and a centrifugal pump, watch water flow through the pipe live, and see exactly where the pump curve and system curve meet to set the real operating flow and head. Use it to explore engineering ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the Fluid Pipe Network & Pump Sizing Lab
- Use the controls to change Pipe length L (m), Pipe diameter D (mm), Static lift Hstatic (m), Shutoff head H₀ (m), Curve steepness a. The simulation reacts instantly.
- Press "Reset to defaults", "Lab report" to start, reset or change what is happening.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Try the 40 L/s operating-flow challenge by widening or shortening the pipe.
- Try the 35 m operating-head challenge by narrowing or lengthening the pipe until the pump throttles down.
- Drag the pump curve steepness and watch the intersection point slide along the system curve.
- Push the static lift up until the warning says the pump can no longer overcome it.
Key ideas you can learn
- A pipe's friction head loss follows the Darcy-Weisbach equation hf = f(L/D)(V^2/2g), where the friction factor f depends on the Reynolds number and pipe roughness.
- The system curve (static lift plus friction loss, which grows roughly with the square of flow) rises with flow rate, while a centrifugal pump's curve falls with flow rate.
- The real operating point of a pump-and-pipe system is wherever those two curves intersect - not simply the pump's rated flow on its datasheet.
- Because friction loss grows with the square of velocity, doubling the flow rate through the same pipe roughly quadruples the friction head loss, which is why oversized pumps waste energy and undersized pipes throttle flow far below expectations.
Where this is used in the real world
Mechanical and civil engineers run exactly this pump-curve/system-curve intersection check when sizing pumps for water supply networks, HVAC chilled-water loops, irrigation systems and industrial process piping, since an oversized or undersized pump wastes energy or starves the system of flow.
Who is this simulation for?
Engineering and technology students, makers, robotics clubs and teachers of design and technology. It gives a hands-on feel for how machines behave before you build a real one.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
Why can't you just read a pump's flow rate off its datasheet without knowing the pipe system it's connected to?
A pump's datasheet only describes its own head-versus-flow curve; the actual flow it delivers depends on where that curve intersects the specific system's head-versus-flow curve (static lift plus friction loss), which is different for every pipe length, diameter and roughness - the same pump delivers very different flow through a short fat pipe than a long thin one.
Why does narrowing a pipe reduce the operating flow rate more than it might seem to?
A narrower pipe raises velocity for the same flow, and friction head loss scales with velocity squared, so the system curve rises much more steeply with flow; this steeper curve intersects the falling pump curve at a noticeably lower flow rate, not just a proportionally smaller one.
Is the Fluid Pipe Network & Pump Sizing Lab free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the Fluid Pipe Network & Pump Sizing Lab work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.