🌊 雷诺数计算器Reynolds Number Calculator

使用说明与常见问题How-to & FAQ

「雷诺数计算器」是什么？What is the Reynolds Number Calculator tool?

按 Re = ρ·v·D ÷ μ（或 v·D ÷ ν）计算流体的雷诺数并判断管流是层流、过渡还是湍流；内置 20 °C 水和空气的密度与黏度。Calculate the Reynolds number Re = ρ·v·D ÷ μ (or v·D ÷ ν) and whether pipe flow is laminar, transitional or turbulent, with the density and viscosity of water and air at 20 °C built in.

如何使用「雷诺数计算器」？How do I use the Reynolds Number Calculator tool?

在「雷诺数计算器」中，填写「流体」、「流速 m/s」、「特征长度（管内径）m」、「密度 kg/m³」、「动力黏度 Pa·s」等参数，结果会随输入实时计算并显示在下方。In the Reynolds Number Calculator: Fill in "Fluid", "Flow speed m/s", "Characteristic length (pipe inner diameter) m", "Density kg/m³", "Dynamic viscosity Pa·s"; results are recalculated instantly as you type.

雷诺数是什么？What is the Reynolds number?

Re = ρvD ÷ μ = vD ÷ ν，是惯性力与黏性力之比，无量纲。数值小时黏性占主导、流动平稳（层流），数值大时容易出现涡旋（湍流）。Re = ρvD ÷ μ = vD ÷ ν, the ratio of inertial to viscous forces, with no units. Low values mean smooth, viscous-dominated (laminar) flow; high values lead to eddies (turbulence).

内置物性从哪来？Where do the built-in properties come from?

20 °C 水：ρ = 998.2 kg/m³，μ = 1.002 × 10⁻³ Pa·s；20 °C、1 atm 空气：ρ = 1.204 kg/m³，μ = 1.825 × 10⁻⁵ Pa·s，均为工程手册中的常用值。温度不同请选自定义。Water at 20 °C: ρ = 998.2 kg/m³, μ = 1.002 × 10⁻³ Pa·s; air at 20 °C and 1 atm: ρ = 1.204 kg/m³, μ = 1.825 × 10⁻⁵ Pa·s — standard engineering-handbook values. Use Custom for other temperatures.

计算结果可以用于作业或工程吗？Can I use the results for homework or engineering?

「雷诺数计算器」使用教科书标准公式（公式写在说明和常见问题中），适合学习和估算核对；涉及安全的工程设计请以规范和实测为准。The Reynolds Number Calculator uses standard textbook formulas (given in the description and FAQ), which is good for learning and checking estimates; for safety-critical engineering follow codes and measured values.

「雷诺数计算器」免费吗？需要注册吗？Is the Reynolds Number Calculator free? Do I need an account?

「雷诺数计算器」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Reynolds Number Calculator is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.