Experimental and numerical investigation of natural convection heat transfer of W-type fin arrays

In this paper, a W-type finned heat sink for natural convection is proposed based on the research of inclined-plate fins. As thermal radiation considered, the natural convective heat transfer performance of W-type fins on a vertical substrate was numerically studied with respect to the variations of geometry. The parallel-plate finned heat sink with and without the surface coating were experimentally studied, to validate the numerical results and the influence of radiation. Moreover, the W-type finned heat sink was experimentally investigated. Experimental results indicate that the W-type finned heat sink achieves the cooling effect of a maximum temperature drop of 4.6°C and an average temperature drop of 2.9°C. Compared to the optimized parallel-plate finned heat sink, the area of heat dissipation decreased by 10%. The optimization results indicate that the average temperature of the substrate tends to decrease first and then increase with the increment of the fin spacing, inclined angle and gap clearance. Meanwhile, there exist peak values for mean heat transfer coefficient of the whole heat sink with the fin spacing, the inclined angle and the gap clearance varied. Furthermore, a characteristic parameter coupled with a series of dimensionless variables is proposed, and the correlation for the inclined plate finned heat sink is suggested with deviation within 12%. It is concluded that for the W-type finned heat sink, the air input is effectively increased in the direction perpendicular to the substrate, leading to smaller thermal resistance. The thermal boundary layer is thinned. Synergy analysis shows that the intersection angle between the direction of velocity and the temperature gradient reduced.