Experimental analysis of double layer microchannel heat sink with distinct fin configurations in upper and lower layers

In the present experimental study, two distinct configurations of double layer microchannel heat sinks (DL MCHS) are proposed. It consists of rectangular parallel channels in the bottom layer and an array of square pin fins in the upper layer. Pin fin height (Hf) in the first configuration is equals to the channel height (Hc) (i.e. Hf/Hc = 1). However, in the second configuration, pin fin height is equivalent to 75 % of Hc such that Hf/Hc = 0.75. The proposed modified DL MCHS configurations are then compared with the conventional double layer microchannel heat sink (CDL MCHS). Hence, the idea of the current work is to develop a novel DL MCHS with improved heat transfer capabilities and reduced pressure penalties. Heat dissipation rate, pressure data and coolant flow behaviour are carefully measured and analyzed. Findings reveal that thermal performance of the modified heat sink with Hf/Hc = 1 is not appreciable because it delivers almost similar to conventional configuration. Whereas, modified heat sink of Hf/Hc = 0.75 has consistently exhibited better heat transfer rate and thermal performance factor. As compared to CDL MCHS, thermal performance factor was found approximate to 38 % higher in this case. Overall thermal and hydraulic performance of the DL MCHS is significantly influenced by the flow pattern of the coolant, which is a result of the novel channel design.