A Quick Overview of Compact Air-Cooled Heat Sinks Applicable for Electronic Cooling—Recent Progress

Abstract

Abstract:This study provides an overview regarding enhancement of an air-cooled heat sink applicable for electronic cooling subject to cross-flow forced convection. Some novel designs and associated problems in air-cooled heat sinks are discussed, including the drawback of adding surfaces, utilization of porous surfaces such as metal foam or carbon foam, problems and suitable applicable range of highly interrupted surfaces (louver or slit) and longitudinal vortex generator. Though the metal foam may accommodate significant surface area, it is comparatively ineffective for air-cooling application due to its much lower fin efficiency, and this shortcoming can be improved by integrating with solid fin. For highly dense fin spacing (e.g., <1.0 mm), cannelure or grooved surface may be a better choice, and fin structure with periodic contraction and expansion may not be suitable for it introduces additional pressure drop penalty. The partial bypass concept, which manipulates a larger temperature difference at the trailing part of heat sink, can be implemented to significantly reduce the pressure drop. Through some certain niche operation, t the thermal resistance of the partial bypass heat sink may be superior to the conventional heat sink. The trapezoid fin surface featuring easier manufacturing and a smaller weight is shown to have competitive performance against traditional rectangular fin geometry. The IPFM (Interleaved Parallelogram Fin Module) design which combines two different geometrical fins with the odd number fins being rectangular shape, and parallelogram shape in even fin numbers, shows 8%-12% less surface than conventional design but still offers a lower thermal resistance than the conventional rectangular heat sink in lower flowrate operation. The cross-cut design shows appreciable improvements as compared to the conventional plate fin design especially in high velocity regime and the single cross-cut heat sinks are superior to multiple cross-cut heat sinks.

An analytically based method to estimate the effective thermal diffusivity of a heat pipe

“…Through some tedious mathematical manipulation and simplification, the final partial differential equation of the heat pipe can be derived as shown in equation (1), where BC at x = 0 is T b , BC at x = L is the insulated tip. The detailed derivation is shown in the appendix:…”

“…For the last 20 years, electronic cooling solutions for notebooks, PCs and servers have been based primarily on steadystate design criteria [1][2][3]. Under these criteria, aluminum extrusion heat sinks or stacked fins made from copper or aluminum are widely adopted as air-cooling thermal solutions [4,5].…”

Modulating fluid rheology and confinement toward augmenting the performance of a double layered microchannel heat sink

“…Conventional heat sink systems, consisting of fins and air-cooling systems, are found to be inadequate, not only due to constraints of physical space but also because of lower thermal properties. 1 Advanced heat dissipation systems deployed include microheat pipes, 2 heat pumps, 3 thermoelectric cooling, 4 boiling heat transfer, 5 and jet impingment. 6 Among these, the liquid-cooled microchannel heat sink (MCHS) is proven effective in cooling microelectronic devices.…”

“…The increased power density that needs to be dissipated, which is often greater than 100 W/cm 2 , requires the development of innovative advanced heat sink systems. Conventional heat sink systems, consisting of fins and air‐cooling systems, are found to be inadequate, not only due to constraints of physical space but also because of lower thermal properties 1 . Advanced heat dissipation systems deployed include microheat pipes, 2 heat pumps, 3 thermoelectric cooling, 4 boiling heat transfer, 5 and jet impingment 6 …”

The Influence of Plate Fin Heat Sink Orientation under Natural Convection on Thermal Performance: An Experimental and Numerical Study

“…The result revealed that the V-type fin array gave better heat transfer performance than the vertical fin array and 'V' fin with bottom spacing type array. Various studies related to the heat sink are found in the literature to enhance heat transfer coefficient [11][12][13][14][15][16][17][18][19][20].…”