Numerical analysis of double-layered microchannel heat sinks with different microchannel heights

A numerical parametric analysis is carried out to investigate the thermal performance of double-layered microchannel heat sinks for different values of the relative channel height and fixed values of the total pumping power, with the additional constraint that the pressure drop be the same in the two layers in order to allow a much simpler header design, which can only include a single inlet and a single outlet. Single-layered microchannel heat sinks are also considered for additional comparisons. The computed results show that, in the hypothesis of this work (i) the ratio of the heights of the upper and lower microchannels only has a marginal effect on the overall thermal resistance but a significant influence on the temperature uniformity of the bottom (heated) surface and (ii) a better temperature uniformity is achieved when the heights of the upper microchannels are larger than those of the lower ones.