Numerical Simulation of Forced Convection in a Microchannel with Realistic Roughness of 3D Printed Surface

This study aims at exploring the thermo-hydraulic performance of 3D printed micro heat exchangers. We performed CFD simulations of single-phase laminar fluid flow and heat transfer in a microchannel with rough surface and compared the results with those obtained in a smooth channel. The model was based on the Navier-Stokes and energy equation. These equations were implemented and solved in the STAR-CCM+ commercial software. The Reynolds number was varied in the range 100-500, while two values of Pr number, 0.71 and 6.0, were chosen. The height of the channel varied between 0.2 and 0.5 mm. The micro-geometry of the surface roughness representing a completely random configuration was reproduced by a 3D scanner. Our results demonstrate that decreasing channel height leads to rising heat transfer rate and pressure drop. At the height of 0.2 mm, a significant rise in pressure drop is evidenced, which indicates a critical height limit for designing such microchannels.