A study on thermal characteristics of double-layered microchannel heat sink: Effects of bifurcation and flow configuration

A comparative study of flow and thermal characteristics has been performed in a double-layered microchannel with bifurcation under parallel and counter-flow layouts using a finite-volume method based open source package OpenFOAM for Re ranging from 50 to 900. The pressure drop, friction factor, flow structures and temperature distribution are compared for both layouts. The effects of bifurcation plate in double-layered microchannel on the overall thermal performance are analyzed and compared with single-layered microchannel with bifurcation reported in the literature. The results show that the overall thermal resistance for the double-layered microchannel with bifurcation is lower compared to that for the non-bifurcated microchannel by approximately 28%. However, the bifurcation plates act as an obstacle in the flow region and hence offer a large pressure drop and increase the pumping power. It is also observed that Nusselt number is increased by 72% for the parallel-flow over the range of Re considered and it is higher than that for the counter-flow for a fixed value of Re. However, difference in Nusselt number is higher in the parallel-flow than that in the counter-flow at low values of Re and this difference diminishes as the flow rate increases. The counter-flow shows a more uniform temperature distribution of the substrate, which is essential for the reliability of any thermal system. Additionally, thermal enhancement factor is obtained for all the cases considered.

Automated summary

A comparative study was conducted on the flow and thermal characteristics in a double-layered microchannel with bifurcation, showing that the bifurcation plates reduce the overall thermal resistance but increase pressure drop and pumping power. Nusselt number is higher in parallel-flow than counter-flow, but the difference is greater at low Re values and diminishes with increasing flow rate. Counter-flow offers a more uniform temperature distribution essential for thermal system reliability.