Cooling High Heat Flux Micro-Electronic Systems using Refrigerants in High Aspect Ratio Multi-Microchannel Evaporators

摘要: Improving the energy efficiency of cooling systems can contribute to reduce emission greenhouse gases. Currently, most microelectronic applications are air-cooled. Switching two-phase would decrease power consumption and allow for reuse extracted heat. For this type application, multi-microchannel evaporators thought be well adapted. However, such devices have not been tested a wide range operating conditions, that their thermal response high non-uniform map typically generated by microelectronics has studied. This research project aims at clarifying these gray areas investigating behavior flow different refrigerants in silicon copper under uniform, transient heat fluxes conditions. The test elements use as source pseudo-chip able mimic CPU. It is formed 35 independent sub-heaters, each having its own temperature sensor, flux measurements made simultaneously. Careful pressure drop component (inlet, microchannels outlet) found micro-evaporators showed importance inlet outlet restriction losses. overall levels section were low enough possibly driven thermosyphon system. transfer coefficients measured uniform conditions very followed V-shape curve. first branch was associated slug regime second annular regime. By tracking minimum level transfer, transition criteria between regimes established, which included effect on transition. Then branch, prediction method used form pattern-based microchannels. A creates important gradients evaporator, data reduction procedure needs adapted include spreading within evaporator. To do so, robust multi-dimensional conduction scheme developed. Once effects taken into consideration, local provided same fluxes, allowing extended Lastly, with proper control mass flow, situations handled micro-evaporators.