Heat Conduction
稳态一维导热热流与温差、截面积成正比,与厚度成反比。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Fourier law | q = kAΔT/L | Fourier 1822 |
| Thermal conductivity | k in W/(m·K) | Material properties |
| Thermal resistance | R = L/(kA) | Thermal circuit |
| Typical k | Cu ≈401, steel ≈50, insulation ≈0.04 | Property tables |
| Steady state | Time-independent field | Analysis assumption |
| Composite wall | Total resistance = ΣRᵢ | Series resistance |
Reference thermal conductivities of common materials and their sources (k varies with temperature, purity and temper)
| Material (room temperature) | Thermal conductivity k | Unit | Source |
|---|---|---|---|
| Pure copper | 401 | W·m⁻¹·K⁻¹ | ASM Handbook Vol. 2 / CRC Handbook |
| Pure aluminium | 237 | W·m⁻¹·K⁻¹ | ASM Handbook Vol. 2 / CRC Handbook (page default) |
| Carbon steel | 50 | W·m⁻¹·K⁻¹ | ASM Handbook Vol. 1 |
| Austenitic stainless steel (304) | 16 | W·m⁻¹·K⁻¹ | ASM Handbook Vol. 1 / ASTM A240 |
| Still air | ≈ 0.026 | W·m⁻¹·K⁻¹ | ISO 22007 / common engineering handbook value |
Note: Fourier's law q = kA·ΔT/L applies to steady one-dimensional conduction; thermal conductivity varies with temperature and temper, so use ISO 22007 or ASTM measured values for precision work.
工作与生活中的相关计算与查询。