What this pipe-sizing model assumes
Links volumetric flow, target velocity, outer diameter, and wall thickness to estimate required inner diameter and actual velocity. Part of the piping preliminary design scenario chain.
Model assumptions
- Incompressible single-phase flow; density variations along the line are not modeled.
- Circular cross-section; wall thickness is uniform; no ovality or corrosion allowance stack-up beyond your entered thickness.
- Design mode uses Q and target v to suggest Di; verify mode uses measured Di to back-calculate Q at a test velocity.
- No fittings catalog, pump curves, or heat loss are included in this calculator.
References & further reading
- Continuity Q = vA for circular ducts; standard undergraduate fluid mechanics texts.
- Piping preliminary design scenario: /tools/scenarios/piping-prelim links pipe sizing → wall thickness → pressure drop.
- GB/T 17395 dimension match notes are on the pipe wall thickness calculator (/tools/pipe-wall-thickness).
Shareable URL
Use “Copy shareable link” below the grid. Query keys (SI): mode=design|test, Q (m³/s), v (m/s), vt (m/s), Do (m), t (m). Press Calculate after opening the link.
Frequently asked questions
- Why do actual velocity and target velocity differ?
- Because the actual inner diameter is Do − 2t; the tool recomputes v from Q and that Di.
- Does this replace piping stress software?
- No. It is for hydraulic sizing/velocity checks only.
- Are results uploaded to the server?
- No. Inputs and outputs stay in your browser session.
Extended copy on this page (headings, assumptions, references, FAQs) may be drafted or localized with AI assistance; engineering judgment and governing codes still apply. Numerical models run locally in your browser as implemented. For contract-critical work, cite primary standards and qualified review.