Numerical Investigation of Thermal Performance of Minichannels with Transversely Patterned Non-Slip and Superhydrophobic Surfaces in Turbulent Flow Conditions

In this study, the thermal performance of a minichannel with transversely patterned non-slip and slip (superhydrophobic) surfaces under turbulent flow conditions was investigated. The minichannel surface consisted of slip and non-slip bands arranged transversely to the flow direction. Numerical simulations of fluid flow through patterned minichannels for a Reynolds number of 5600 under constant heat flux conditions were performed using CFD software Star-CCM+. The k-ω turbulence model with a coupled solver was used for simulating flow through minichannels. Several cases were simulated to understand the effects of non-slip to slip ratio and width of non-slip bands on pressure drop and thermal performance of circular minichannels. Several non-slip to slip ratios and different non-slip band widths were considered. Boundary layer thickness, friction factor, slip velocity, shape factor, Nusselt number and performance evaluation criterion (PEC) were calculated to understand the effects of non-slip to slip ratio on thermal performance. The results reveal that a decrease in non-slip to slip ratio and increase in non-slip width lead to a reduction in pressure drop and enhancement in heat transfer. Furthermore, a specific non-slip to slip ratio and a non-slip width of 0.8d was found to yield a 40% reduction in pressure drop and a PEC value of 3.4. In summary, the numerical simulations show that microchannels consisting of slip and non-slip bands arranged transversely to the flow direction can lead to enhanced thermal performance under turbulent flow conditions.