Efficiency of a straight fin of uniform cross-section: η_fin = tanh(m·L) / (m·L).
Formula
$$ m = \sqrt{\frac{2 h}{k \cdot t}}, \quad \eta_\text{fin} = \frac{\tanh(m L)}{m L} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $h$ | External film coefficient | W/(m²·K) | convection |
| $k$ | Fin conductivity | W/(m·K) | material property |
| $t$ | Fin thickness | m | geometry |
| $L$ | Fin length from base | m | geometry |
| $m·L$ | Dimensionless fin parameter | - | derived |
Sources
- Incropera - Fundamentals of Heat and Mass Transfer.