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Pipe velocity & Reynolds number calculator

Engineering calculators (Beta)

Find average velocity and Reynolds number from bore, flow and fluid properties.

Inputs

Choose units and enter numbers. Full-width digits and fractions such as 1/8 or 1 3/8 are accepted. Changing a unit converts the entered value.

Results

Reference calculation only. Results do not certify suitability for an actual design or its safety.

Diagram

Inputs: select a blue symbol to edit Results: red-orange values and lines

Formula and applicability

A = π D² / 4, v = Q / A, Re = ρ v D / μ

Displayed values are rounded. Diagrams illustrate the calculation conditions. Initial material and fluid properties are examples; replace them with values for the actual material, temperature and conditions.

Reference
Using this information as a reference

Equations assume particular loads, supports and deformation ranges. Check inputs, units and the applicability of each equation. Diagrams explain conditions; they are not manufacturing drawings or proof of safety.

Material values are typical values or reference ranges, not certified product properties or ready-to-use design allowables. They vary with standards, product form, dimensions, temper and temperature. Check the specifications and inspection certificates for the actual product.

Displayed safety factors and checks apply only to the supplied inputs and calculation model. They do not automatically establish the safety of a complete design, including code compliance, service life, fatigue or joints. For actual design, manufacture and use, separately verify applicable regulations and standards, product specifications, and the necessary tests and engineering review.

Calculations do not submit input values to a server. Results are not an automatic code-compliance or safety determination.

この計算で求められること

内径・体積流量・流体物性から流速とReを求めます。

入力・結果・適用条件を確認する

選択した形状・計算方法により、使う項目は変わります。実際の計算は上の図と入力欄で行えます。

主な入力

  • 管の内径 D (mm / cm / m)
  • 体積流量 Q (L/min / m³/h / m³/s)
  • 密度 ρ（入力例） (kg/m³ / g/cm³ / g/L)
  • 粘度 μ（入力例） (Pa·s / mPa·s / cP)

得られる結果

  • 平均流速 v (m/s)
  • レイノルズ数 Re (—)
  • 流路断面積 A (mm²)
  • 動圧 ρv²/2 (Pa)

計算式の概要

A = π D² / 4, v = Q / A, Re = ρ v D / μ

満管の円管を流れる定常・非圧縮性のニュートン流体を想定します。密度・粘度は実際の温度で指定してください。圧力損失・圧縮性・開水路は計算しません。

現在選択中の方法には、操作欄の「計算式・適用条件」を使ってください。参考計算であり、設計全体の安全性を保証するものではありません。

関連する計算

What this calculator does

Find average velocity and Reynolds number from bore, flow and fluid properties.

Inputs, outputs and applicability

The selected model determines which of these inputs and outputs apply. Use the working diagram and input panel above to calculate.

Inputs

  • Pipe bore D (mm / cm / m)
  • Volume flow Q (L/min / m³/h / m³/s)
  • Density ρ (example) (kg/m³ / g/cm³ / g/L)
  • Dynamic viscosity μ (example) (Pa·s / mPa·s / cP)

Calculated results

  • Mean velocity (m/s)
  • Reynolds number (—)
  • Flow area (mm²)
  • Dynamic pressure (Pa)

Formula overview

A = π D² / 4, v = Q / A, Re = ρ v D / μ

Steady incompressible Newtonian flow in a full circular pipe. Use density and viscosity at the actual temperature. Pressure loss, compressibility and open channels are excluded.

The displayed formula and conditions in the working panel apply to the currently selected model. Reference calculation only; it does not certify a complete design.

Related tools

入力する単位を確認・換算する

Check and convert input units

数値の感覚を、図と動きで確かめる

説明用の別モデルです。適用条件を確認してください。数値は自動転記しません。

See the idea in diagrams and motion

A separate explanatory model. Check its assumptions; values are not transferred.