The impact of roughness parameters on laminar convective heat transfer applied to additive manufactured minichannels

Roughness is an inherent feature of additively manufactured surfaces that can influence thermal performance. This study employed Computational Fluid Dynamics (CFD) to investigate the impact of the roughness characteristics, including average roughness height, root-mean-square height, skewness, and kurtosis, on the laminar convective heat transfer in minichannels. It was found that, compared to Gaussian roughness, the positively skewed, platykurtic and leptokurtic distribution increased heat transfer by 14.17, 15.50, and 11.22 %, while a marginal increase in the friction factor (almost 1.50 %) was observed. However, the Nusselt number of the negatively skewed distribution was 8.15 % less than the Gaussian, and its friction factor was also reduced by 1.30 % below Gaussian values. The finding demonstrated the capacity of rough surfaces with high peaks as a passive heat transfer enhancement method with marginal penalty in pressure drop.