CFD Simulation of Flow and Heat Transfer of V-Shaped Wavy Microchannels

Due to its high heat transfer property, microchannel heat sink has been widely applied in thermal management, microelectronic cooling and energy conversion. To develop a microchannel heat sink featuring low pressure drop ΔP and a high heat transfer property, a V-shaped wavy microchannel (VWM) is designed and CFD simulation is carried out. Subsequently, the influences of wave amplitude A, wave length λ and inlet velocity u on the Nusselt number Nuave, the Dean Vortexes and ΔP are studied. Furthermore, based on the performance evaluation criteria (PEC), the optimal parameters of A, λ and u are chosen. Next, the influence of microchannel number N is studied at the same pump power. Eventually, the optimal VWM heat sink is compared with the V-shaped straight microchannel (VSM) heat sink and the rectangular-shaped straight microchannel (RSM) heat sink. The results show that many Dean Vortexes periodically emerge in the V-shaped wavy microchannel, particularly at the wave peak and valley. These Dean Vortexes are capable of thinning the thermal boundary layer, which significantly strengthens heat transfer. As A and u increase while λ decreases, the area, number and severity of the Dean Vortexes increase, and thus both Nuave and ΔP also increase. In the present study, the PEC first increases and then decreases, reaching its maximum value when A = 0.3 mm, λ = 5 m and u = 1.0 m/s. At the same pump power, both the heat transfer area and the total Dean Vortex number increase with the increase in N, leading to a decrease in the thermal resistance R and the maximum temperature Tmax. Compared to the VSM and RSM heat sinks, the optimal VWM heat sink decreases Tmax by 29.93 K and 38.03 K, decreases R by 50.46% and 56.68%, increases have by 156.42% and 155.43% and increases PEC by 137% and 130.78%, respectively.