Natural convection from rectangular interrupted fins

•Natural convection from interrupted finned heatsinks is investigated in this study.•Compact relations for optimum interruption length are introduced.•The correlation is validated by results of an independent numerical model.•An experimental study is conducted to verify the numerical results.

Steady-state external natural convection heat transfer from vertically-mounted rectangular interrupted fins is investigated numerically and experimentally. FLUENT software is used to develop a 2-D numerical model for investigation of fin interruption effects. A custom-designed testbed was developed and 12 different aluminum alloy heatsinks with various geometric dimensions are machined and tested to verify the theoretical results. A comprehensive experimental–numerical parametric study is performed to investigate the effects of fin spacing, and fin interruption. Our results show that adding interruptions to vertically-mounted rectangular fins can enhance the thermal performance considerably and that an optimum fin interruption exists. A new compact correlation is proposed for calculating the optimum interruption length. The results of this work can be used to improve natural heat transfer from enclosures in a variety of electronics, power electronics and telecom applications.