Abstract:How to dissipate heat effectively is the important topic for high power microwave devices. The conventional straight micro-channel heat sink which has been considered as an effective heat removal tool has the attributes of simple structure, large convective heat transfer coefficient and high surface area to volume ratio. But the increase of temperature of the dissipating surface along the direction of the fluid flow will influence the stability of electronic components. For jet impingements, the way to obtain a quite uniform temperature distribution is the use of matrix of jets, which has thinner temperature boundary, higher temperature gradient and larger heat exchange coefficient by fluid perpendicular impinging cooled object. The micro-channel heat sink combined with jet impingement not only has large heat exchange coefficient but also improves the temperature uniformity of the cooled object. In this paper, performance of micro-channel heat sink combined with jet impingement for high heat flux density cooling is simulated with numerical method. The effects of different jet apertures on the heat transfer and flow characteristics are analyzed. The results show that increasing the pore size away from the exit is beneficial to increase the heat transfer efficiency and reduce the flow resistance. The optimized heat transfer coefficient of the micro-channel heat sink combined with jet impingement is closed to 39 000 W/(m2·K), when the mass flow rate is 14 g/s.