Modern advancements in transistor technology have pushed thermal dissipations from power electronics near the edge of the capability of single-phase micro-channel designs. To alleviate this problem, researchers have begun investigating enhancements to these designs, using methods such as pin fins, turbulators, and impinging jets. These techniques can potentially enhance the convective thermal performance by a factor of 2 to 3, although they do incur a similar magnitude pressure penalty. However, because of the requirements of electrical isolation and mechanical assembly, much of this benefit is tempered, as the convective thermal resistance is only a small fraction of the total resistance. This limitation can be removed through the use of an integral package design where the heat sink passages are fashioned in the electrical stack, which can reduce the conductive resistance until convective enhancements are significant again. These methods include fabrication of micro-channels directly into the active metal braze substrate and potentially even the electrical insulation layer. Thus, while a traditional, non-integral design only experiences a 5% overall benefit when the convective resistance is reduced by 50%, an integral package can have a 20 to 30% improvement for the same enhancement. To examine this capability, a series of computational fluid dynamics studies were conducted to study the performance of several integral micro-channel heat sink configurations. These simulations determined the response for a range of coolants, flowrates, device power dissipations, and operating conditions. These results will serve as a baseline for further development of enhanced, integral micro-channel designs.
Heat Transfer Coefficient and Flow Characteristics of Hot Steel Plate Cooling by Multiple Inclined Impinging Jets
