Does this select a DN, NPS or Schedule 40 pipe?

No. Nominal designation, wall series, material, tolerances and the resulting minimum inside diameter must come from the applicable controlled product specification.

Does it recommend a safe or economic velocity?

No. Any velocity limit is a documented design input, not a recommendation generated by this worksheet.

Does the result verify pressure drop or cavitation?

No. Pressure loss, Reynolds number, transients, noise, erosion, cavitation and fitness for service are outside this arithmetic.

What diameter is used?

The actual internal flow diameter at the assessed condition, not nominal DN/NPS and not outside diameter.

General engineering arithmetic — not an ISO pipe selector

Circular-Pipe Flow–Area Arithmetic

Relate actual volumetric flow, cross-sectional mean velocity and actual circular inside diameter at one documented operating state. The worksheet does not invent a standard pipe size or design velocity.

No DN/NPS inferenceNo Schedule 40 tableNo safety verdict

结果

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Actual volumetric flow Q

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Cross-sectional mean velocity

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Internal flow diameter

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Circular flow area

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Dimensional arithmetic only.

A=πd²/4; Q=A v̄; d=√(4Q/(πv̄)); v̄=4Q/(πd²)

Q is actual volumetric flow at the assessed state [m³/s], A is the full circular internal flow area [m²], d is actual internal flow diameter [m], and v̄ is area-average velocity normal to that cross-section [m/s]. The equations are dimensional geometry and general engineering flow arithmetic; they are not presented as an ISO sizing formula.

Exact conversion basis

1 L=10⁻³ m³; 1 h=3600 s; 1 min=60 s; 1 in=0.0254 m exactly; 1 ft=0.3048 m exactly; and 1 US gallon=231 in³=0.003785411784 m³ exactly. “US gal/min” is explicitly not an Imperial gallon.

No automatic pipe selection

ISO 6708:1995 defines the DN alphanumeric designation system; it does not make DN equal to actual ID. NPS, outside diameter, schedule/wall series, material, manufacturing tolerance, lining, corrosion allowance and temperature/pressure effects are separate product-design inputs.

NEEDS_LICENSED_SOURCE: any exact ASME B36.10/B36.19 or other product-standard dimension used to choose a purchasable pipe. This worksheet intentionally contains no normative pipe-dimension rows.

未计算

Pressure drop, pump duty, Reynolds number, roughness, fittings or elevation effects.
Cavitation, flashing, compressibility changes, two-phase flow, erosion, water hammer, surge or acoustic/noise response.
Economic or safe velocity, minimum wall, pressure rating, corrosion/erosion allowance or code compliance.
Whether a selected nominal product has sufficient minimum ID after tolerances and service allowances.

资料来源

University of Dayton, Volumetric Flowrate, Velocity and the Continuity Equation (2022); NIST SI Units — Length; NIST Handbook 44 Appendix C conversion table; ISO 6708:1995.