Optimization of a cylindrical heatsink with L-shaped fins to minimize thermal resistance variation by installation angle

Abstract

Light Emitting Diode (LED) lighting can be installed at various angles depending on user preferences. However, the cooling performance of heatsinks may decrease with changes in installation angle, potentially affecting the lifespan of LED lighting. This study considered L-shaped fins on a cylindrical base in an effort to minimize variations in thermal resistance with changes in installation angle while reducing the heatsink mass. Thermal resistance was analyzed based on the area removed from rectangular fins to form L-shaped fins. The heatsink's thermal resistance was predicted across a range of installation angles through numerical analysis using ANSYS FLUENT, and the accuracy of these predictions was validated experimentally. By varying the fin deletion area, fin count, and cylindrical base radius, the ranges of porosity factor and finning factor were determined as 0.7054 ≤ φ ≤ 0.7494 and 2.1069 ≤ ψ ≤ 3.9874, respectively. With the heatsink installation angle varying from 0° to 180°, the rate of change in thermal resistance for a cylindrical heatsink with rectangular fins (without a deletion area) was large, reaching 24 %, while that for a cylindrical heatsink with L-shaped fins was significantly reduced, staying within 10 %. A correlation equation to estimate the thermal resistance of an L-finned cylindrical heatsink was proposed, predicting thermal resistance with an error margin of up to 15 %. The cylindrical heatsink with L-shaped fins developed in this study is expected to be applicable in various LED lighting systems requiring both reduced heatsink mass and minimal thermal resistance variation with changes in installation angle.