Heat Sink Pressure Drop Research Articles

Experimental and Numerical Investigation of Single-Phase Liquid Cooling for Heterogeneous Integration Multichip Module

Abstract The variety of new electronic packaging technologies has grown significantly over the last 20 years as a result of market demands for higher device performance at lower costs and in less space. Those demands have pushed for heterogeneous packaging, where computer chips with different stack heights are closely packed, creating nonuniform heat flux and temperature and additional challenges for thermal management. Without implementing an appropriate thermal management strategy for heterogeneous packages, large temperature gradients can be observed within the package, which would increase the thermal stresses on the chip and raise reliability issues. To mimic this real-life scenario of such packaging, an experimental setup was designed and built. The design of the new experimental setup consists of four identical 1.2 cm × 1.2 cm ceramic heaters, each of which is connected to a separate power supply and can reach a heat flux of 140 W/cm2. Accordingly, this mock package is capable of delivering different power levels to mimic different multicore microprocessor conditions. To give the heater the ability to move precisely in the x-, y-, and z-directions, each heater is mounted to an XYZ linear stage. Deionized water (DI) was used as the working fluid, and a pin-fin heat sink was used to run the initial steady-state tests on the experimental rig. The tests showed how different flow rates at a constant fluid temperature and input power affect the temperatures of the heaters and the thermohydraulic performance of the heat sink. In addition, a three-dimensional numerical model has been developed and validated with experimental data in terms of heat sink pressure drop and the temperatures of the heaters.

Towards Thermal-Acoustic Co-Design of Noise-Reducing Heat Sinks

Several thermal management applications involve fan-mounted heat sinks that result in fan-generated noise as an undesired by-product. These applications require noise reduction and attempt to reduce noise using separate muffler devices. However, space for separate heat-sinking and noise-reducing functionalities may be challenging in high-performance applications such as electronics cooling, data centers, automotive, aviation, and various others. A first-principles-based approach for combined heat sinking and noise reduction in the same functional volume is discussed in this paper. This paper reports on thermal-acoustic co-design of 3-D periodic porous foam structures. In order to enable a design strategy, an analytical framework that characterizes the governing performance indicators of both acoustic and thermo-fluid design on a unifying platform is laid out. A combination of analytical and phenomenological models is used to predict the absorption coefficient, transmission loss (TL), and other acoustic performance indicators. For thermal predictions, an experimentally validated semiempirical model is presented to estimate thermal resistance and static pressure drop of foam heat sink as a function of geometrical parameters as well as flow rates. Octave-band weighted values of acoustic indicators are then compared against thermal indicators to investigate thermal-acoustic co-design aspects. As hydraulic pore radius of porous foam decreases, the acoustic absorption coefficient increases reaching local maxima. Concomitantly, the pore radius decrease not only increases the absorption coefficient while dissipating heat, but also increases the heat sink pressure drop. For a chosen sound absorption region of interest, there exists a particular static pressure drop that maximizes heat sink dissipation for a given radius. The paper concludes by reporting TL and heat sink thermal performance for a generic electronics cooling configuration while elucidating the nuances of the proposed heat sink design using a thermal-acoustic index.

Measurement of performance of plate-fin heat sinks with cross flow cooling

This work assesses the performance of plate-fin heat sinks in a cross flow. The effects of the Reynolds number of the cooling air, the fin height and the fin width on the thermal resistance and the pressure drop of heat sinks are considered. Experimental results indicate that increasing the Reynolds number can reduce the thermal resistance of the heat sink. However, the reduction of the thermal resistance tends to become smaller as the Reynolds number increases. Additionally, enhancement of heat transfer by the heat sink is limited when the Reynolds number reaches a particular value. Therefore, a preferred Reynolds number can be chosen to reduce the pumping power. For a given fin width, the thermal performance of the heat sink with the highest fins exceeds that of the others, because the former has the largest heat transfer area. For a given fin height, the optimal fin width in terms of thermal performance increases with Reynolds number. As the fins become wider, the flow passages in the heat sink become constricted. As the fins become narrower, the heat transfer area of the heat sink declines. Both conditions reduce the heat transfer of the heat sink. Furthermore, different fin widths are required at different Reynolds numbers to minimize the thermal resistance.