Thermal-hydraulic performance analysis and multi-objective optimization of a microchannel with staggered semi-elliptical ribs

To enhance the cooling capacity of traditional microchannels for high heat flux electronic devices, a microchannel design with staggered semi-elliptical ribs is proposed in this paper. Through numerical simulations, the flow characteristics of the designed microchannel are compared with those of a smooth one, and the effects of rib width (W_r), rib height (H_r), and rib length (L_r), on the thermal-hydraulic performance are investigated under laminar flow conditions. The results show that the periodically arranged ribs induce periodic vortices within the microchannel, effectively promoting fluid mixing and enhancing heat transfer. W_r and H_r have similar effects on microchannel performance, with an increase in them leading to an enhanced thermal performance at the expense of deteriorated hydraulic performance. Additionally, L_r has a comparatively weaker influence, with both the heat transfer and flow resistance initially growing with increasing L_r and then declining. To strike a balance between the two performances, a multi-objective optimization on the three geometrical parameters is conducted at a Reynolds number (Re) of 440. Combined with simulation data, artificial neural networks are trained as surrogate models, and a multi-objective genetic algorithm is employed to derive the Pareto front. Using the TOPSIS decision-making method, an optimal compromise solution is determined as W_r = 0.2415 mm, H_r = 0.0976 mm, and L_r = 0.6486 mm. Performance testing on the optimized microchannel reveals that it exhibits high heat transfer, middle flow resistance, and excellent overall performance, with the performance evaluation criterion (PEC) falling between 1.572 and 1.723 within the Re range of 220–660.