Thermofluids performances on innovative design with multi-circuit nested loop applicable for double-layer microchannel heat sinks

This study numerically proposes a novel microchannel heat sink design named multi-circuit nested loop (ML) to strength the thermal performance of double-layer microchannel heat sinks (DMCHS). The ML is introduced into the DMCHS to enhance the thermal characteristics and is compared with the traditional straight DMCHS. Due to the complexity of the ML-DMCHS, 4 different working conditions on inlets and outlets are designed to find the optimal one. Based on the analysis of the thermal gradients on substrate, flow characteristics of coolant, overall thermal resistance and thermal performance factor, it is found that the novel ML-DMCHS not only can significantly reduce the peak temperature, but also offer better temperature uniformity on substrate. The peak temperature on substrate can be reduced up to 34 K when compared with traditional parallel straight double-layer microchannels (P-DMCHS). Furthermore, the inner cooling circuit in ML-DMCHS shows greater impact on the lowest temperature on substrate, while the outer cooling circuit affects more on the peak temperature.