Micro-channel heat exchanger optimization

A complete two-dimensional flow/thermal model of the micro-channel cooler is developed. Optimization of the design parameters with this model is demonstrated for the case of a 1 kW/cm² heat flux with the top surface at 25°C. For this case, pure water could be used as the coolant, or 92% water/8% methanol (-5°C freezing point) if the heat is to be dumped to ice/water. The flow rate should be about 50 cc/s per cm² of surface area. The distribution manifold channel spacing (center-to-center) should be 333 μm (30 channels/cm). The fin height should be about 167 μm (H_F/L =1). The distribution manifold channel widths should be about 200 μm (W/L=0.6). The micro-channels should be between 7 μm and 14 μm wide, while the ratio of fin thickness to micro-channel width should be from 0.5 to 1.0. With these design parameters, an effective heat transfer coefficient (surface heat flux divided by surface to coolant inlet temperature difference) on the order of 100 W/cm² K will be achieved with a total pressure drop of only about 2 bar