Effect of tip clearance on the heat transfer and pressure drop performance in the micro-reactor with micro-pin–fin arrays at low Reynolds number

To optimize and improve the thermal and hydrodynamic performance of micro-reactors with micro-pin–fin arrays (MPFAR), the effect of tip clearance on the performance of the heat transfer and pressure drop at low Reynolds number was investigated by computational fluid dynamics (CFD). Unlike with high Reynolds number flow, it was found that the heat transfer and pressure drop performance in the case of low Reynolds number is quite sensitive to the tip clearance, and the introduced tip clearance can enhance the heat transfer and reduce the pressure drop effectively. Previous correlations were examined and found to overpredict the average Nusselt number and friction factor. New heat transfer and friction factor correlations accounting for the effect of tip clearance were developed, providing a valuable approach to the design and optimization of the tip clearance of the MPFAR. Finally, a series of experiments was carried out to validate the numerical simulation approach, and the experimental results agreed well with those from simulation.