Minimizing Pressure Drop and Maximizing Heat Transfer in a Microchannel Heat Exchanger Using COMSOL

Electronic devices and compact energy systems are becoming smaller and more powerful, which creates serious challenges for thermal management. Large amounts of heat must be removed from very small areas without exceeding safe operating temperatures. Microchannel heat exchangers (MCHXs) can address this problem because they provide a high surface-to-volume ratio and strong convective heat transfer in a compact volume. In this work, a three-dimensional copper microchannel heat sink is developed and analyzed using COMSOL Multiphysics 6.2 by coupling the Laminar Flow and Heat Transfer in Solids and Fluids interfaces. The baseline geometry consists of ten parallel rectangular microchannels with a width of 1mm and a fin thickness of 0.5mm. The heat sink is subjected to a uniform heat flux of 5x104 W/m2 and is cooled by water entering at 293.15 K. The study explores how geometric parameters such as channel width, fin thickness, and channel count influence both thermal performance (maximum temperature, thermal resistance, and Nusselt number) and hydraulic performance (pressure drop and pumping power). The results show that narrower channels and thinner fins can significantly reduce maximum temperature and improve temperature uniformity, but they also increase pressure drop and required pumping power. The optimized configuration achieves a good balance between low thermal resistance and moderate pressure drop. The modeling approach provides a simple, repeatable procedure that can be extended to more complex geometries, alternative coolants, and optimization frameworks.