CFD analysis and experimental verification on a new type of air-cooled heat sink for reducing maximum junction temperature

Abstract

This paper investigates a new type of plate-fin heat sink having a rectangular fin-cut at the entrance while containing a fin-protrusion part at the rear of the heat sink. The design not only offers appreciable heat transfer enhancement without pressure drop penalty, but also pronouncedly reduces the maximum junction temperature (Tmax). It is experimentally validated that the effective thermal resistance can be reduced by 5.5–7.2% under the heating load of 250 W, and the temperature at the rear heat source can be reduced by about 2.5 K under same pumping power compared to the original plate-fin heat sink. Triangular fin-protrusion applying at the rear part shows more pronounced improvement on thermal performance compared to a rectangular one because of better heat spreading. Meanwhile, by placing a partition baffle below the rectangular fin-cut can further reduce the Tmax to reach as low as 354.5 K under the pumping power of 0.3 W. The effect of partition baffle and fin angle (θ) is quantitatively studied in more details. When θ is increased over 45°, the partition baffle shows further improvement on Tmax at fixed pumping power. The lowest Tmax is obtained when the fin angle (θ) of the fin-protrusion area reaches 65° It is also observed that the rectangular fin-cut is superior to a triangular one, suggesting a “Coanda-like” effect. In addition, a correlation is developed to predict the Tmax of the new air-cooled heat sink. The predictive deviations of the correlation against numerical results are within ±2.0 K, showing a reasonably predictive ability.