Electronics cooling

About: Electronics cooling is a research topic. Over the lifetime, 1135 publications have been published within this topic receiving 17608 citations.

Effect of microscale thermal conduction on the packing limit of silicon-on-insulator electronic devices

Abstract: It is pointed out that silicon-on-insulator (SOI) electronics have a buried silicon dioxide layer which inhibits device cooling and reduces the thermal packing limit, the largest number of devices per unit substrate area for which the device operating temperature is acceptably low. Thermal analysis yields the packing limit of SOI MOSFET devices in terms of the device power and the limit on the channel temperature. Thermal conduction is microscale if it is significantly reduced by the boundary scattering of heat carriers, electrons in aluminum, and phonons in silicon. If microscale effects are not considered, the packing limit is overpredicted by 22% for a substrate temperature of 300 K and 100% for substrate temperature of 77 K. >

Design and optimization of pin fin heat sinks for low velocity applications

Abstract: In a number of electronic cooling applications, the air flow velocity and direction are not very well defined or controlled. In these applications, pin fin heat sinks are widely used because they are not sensitive to air flow direction. A study was undertaken to optimize the design of pin fin heat sinks for use in low velocity applications where there is plenty of open space around for the air to bypass the heat sink, if it encounters high pressure drop across it. The goal of this study was to maximize the thermal performance and keep the design such that it is easily manufacturable to keep the cost low. A special test fixture using a heat flux meter was designed to test the heat sinks for thermal performance. Several aluminum pin fin heat sinks having a 25/spl times/25 mm base size, heights from 5 to 25 mm, pin arrays of 4/spl times/4 to 8/spl times/8, and pin fin cross sections from 1.5/spl times/1.5 mm to 2.5/spl times/2.5 mm were fabricated and tested for thermal performance. Some of the commercial aluminum heat sinks with various surface finishes (such as black anodized, gold chromated, clear anodized and untreated) were also evaluated to determine the effect of surface treatment on thermal performance. The heat sink tester and the test data for the heat sinks used in this optimization study are reviewed in this paper. The results show that it is possible to design an optimum pin fin heat sink for any flow situation. However, it is not realistic to have several heat sink designs to cover various applications. In low velocity (about 1 m/s or less) open flow situations, the best compromise for pin fin heat sink with about 25/spl times/25 mm base size and heights up to 15 mm is the 6/spl times/6 pin fin configuration with fin cross-sections of 1.5/spl times/1.5 mm.

Induction electrohydrodynamics micropump for high heat flux cooling

Abstract: Induction electrohydrodynamics (EHD) has been investigated as a possible means of pumping liquids through microchannel heat sinks for cooling microprocessors. A pump utilizing induction EHD has been microfabricated and tested. The experimental results matched the predictions from correlations to within 30%. Based on this, a micropump has been designed which is miniaturizable to a level where it can be integrated into the microchannels. The micropump utilizes a vibrating diaphragm along with induction EHD for pumping. The vibrating diaphragm does not cause any net flow by itself but causes high local bulk fluid velocities which lead to an increase in the power drawn from the electrodes and an increase in efficiency of EHD, both of which lead to a higher flow rate. The performance of the pump is predicted using an experimentally validated numerical model. The numerical model solves the three-dimensional transient fluid flow and charge transport problem due to simultaneous actuation of EHD and the vibrating diaphragm. Numerical results for micropumps integrated into trapezoidal microchannels are presented. The results indicate that the proposed micropump design has significant potential for microelectronics cooling applications: It is easy and inexpensive to fabricate, needs no added space, and can achieve the high flow rates needed.