Experimental and numerical investigation of heat and mass transfer in non-uniform wavy microchannels

To improve the thermal performance of microchannel heat sinks, non-uniform wavy microchannels were designed and their heat and mass transfer performance were studied by a numerical method. The effects of the Reynolds number, Re, and the peak deviation position on the thermal-hydraulic performances of the microchannels were analyzed based on the performance evaluation criteria (PEC) and the principle of entropy generation. The numerical analysis indicated that the heat transfer performance of the divergent wavy microchannel (denoted as MCH-41, with the peak position far from the fluid entrance) exhibited better heat transfer performance than that of the uniform (denoted as MCH-05) and the convergent wavy (denoted as MCH-14) microchannels. The thermal resistance and entropy generation of MCH-41 were lower than those of MCH-05 and MCH-14. Moreover, a flow visualization platform was established to observe the periodic pulsation characteristics of the fluid at Re = 693. The enhanced heat and mass transfer mechanism of the divergent wavy microchannel was further analyzed. The experimental results were in agreement with the numerical simulation results. •Fluid flow mechanism and heat transfer performance of nonuniform wavy microchannel were studied.•Temperature and velocity distribution through numerical simulation were investigated.•Larger Nusselt number and lower entropy generation number were obtained for divergent wavy microchannel.•Better thermal performance was found for divergent wavy microchannel.