Suscripción a Biblioteca: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Effect of Electrode Configuration on the Heat Transfer Performance of a Concentrated Heat Source

Get access (open in a dialog) DOI: 10.1615/IHTC15.tmg.008553
pages 8117-8125

Sinopsis

In this study, enhancements of LED cooling using ionic wind subject to various electrode configurations are presented. A total of six needle type electrodes, including sharp, 0.08 R, 0.12 R, 0.37 R, 0.49 R and flat tip, are used in the experimentation. The effects of electrode configuration, vertical separation height, and tilt angle on the cooling performance of a LED are reported in this study. With the rise of supplied voltage, the thermal resistance is reduced and a maximum 50% reduction is achieved before the spark-over voltage. For the same supplied voltage, the thermal resistance with a larger vertical separation is also higher. However, the operational range is also longer. The effect of tilt angle on the cooling performance of LED depends on the supplied voltage. For a supplied voltage less than 6.5 kV with a tip radius of 0.12 R, it is found that the thermal resistance is reduced when the tilt angle is reduced. However, the trend is reversed when the supplied voltage is higher than 6.5 kV where the thermal resistance of a smaller tilt angle is lower than that of a larger tilt angle. For the same mesh ground, the effect of electrode configurations cast little influence on the final thermal resistance. All types of electrode can provide an approximately 50% reduction of its original thermal resistance. However, the corresponding threshold voltage and operational voltage differs significantly. The threshold voltage is lowest for the sharp needle and is increased with the rise of tip radius. On the other hand, the corresponding operational range becomes narrower when the tip radius is increased. Nevertheless the spark-over voltage is also insensitive to change of electrode configuration.