Orientation Effects on Heat Dissipation Performance of Plate-fin Heat Sink for LED Application
Author(s): ZHANG Jian-xin, YANG Qing-xin, NIU Ping-juan, WANG Ning, JIANG Yi-na
Pages: 846-853
Year: 2015 Issue: 7
Journal: Chinese Journal of Luminescence
Keyword: LED cooling; natural convection; plate-fin heat sink; numerical simulation; inclination angle;
Abstract: The plate-fin heat sink is widely used in LED lamp for application of multi-angle illumi-nation. According to the key structures of a LED projection lamp, the orientation effects on heat dis-sipation performance of plate-fin heat sink with natural convection cooling were researched under 3 driving currents and 7 inclination angles between illumination direction and gravity direction. Based on the validity and accuracy of numerical simulation verified by experimental results, the thermal mechanisms with respect to maximum excess temperature and temperature uniformity were investiga-ted through analyzing temperature and flow data derived from numerical simulation. The obvious differences of air velocity distribution in the flow channel of fins are found among inclination angles, these differences are the main reason of sensitive orientation effect about maximum excess tempera-ture and temperature uniformity. In addition, air velocity difference between upstream and down-stream around the measuring point with maximum temperature can be used to quantitatively interpret the variation trend of temperature uniformity in different inclination angles. Furthermore, the effects of inclination angle and fin spacing on the maximum excess temperature were analyzed. The results show that the heat dissipation performance of plate-fin heat sink with optimal fin spacing has high orienta-tion sensitivity, so the study of orientation effects on the air flow and heat transfer of plate-fin heat sinks is an indispensable task in the thermal design of LED with multi-angle illumination function.
Pages: 846-853
Year: 2015 Issue: 7
Journal: Chinese Journal of Luminescence
Keyword: LED cooling; natural convection; plate-fin heat sink; numerical simulation; inclination angle;
Abstract: The plate-fin heat sink is widely used in LED lamp for application of multi-angle illumi-nation. According to the key structures of a LED projection lamp, the orientation effects on heat dis-sipation performance of plate-fin heat sink with natural convection cooling were researched under 3 driving currents and 7 inclination angles between illumination direction and gravity direction. Based on the validity and accuracy of numerical simulation verified by experimental results, the thermal mechanisms with respect to maximum excess temperature and temperature uniformity were investiga-ted through analyzing temperature and flow data derived from numerical simulation. The obvious differences of air velocity distribution in the flow channel of fins are found among inclination angles, these differences are the main reason of sensitive orientation effect about maximum excess tempera-ture and temperature uniformity. In addition, air velocity difference between upstream and down-stream around the measuring point with maximum temperature can be used to quantitatively interpret the variation trend of temperature uniformity in different inclination angles. Furthermore, the effects of inclination angle and fin spacing on the maximum excess temperature were analyzed. The results show that the heat dissipation performance of plate-fin heat sink with optimal fin spacing has high orienta-tion sensitivity, so the study of orientation effects on the air flow and heat transfer of plate-fin heat sinks is an indispensable task in the thermal design of LED with multi-angle illumination function.
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