Numerical analysis of fluid flow and heat transfer characteristics in single crystal diamond microchannels with ribs and secondary channels

To meet the heat dissipation requirements of high-frequency and high-power electronic devices, single crystal diamond microchannels (SCD-MC) with secondary channels and rib combinations are proposed. The fluid flow and heat transfer characteristics in SCD-MC with various secondary channels and rectangular rib combinations are investigated through numerical simulations. The comprehensive performance and energy saving effect of the microchannel were evaluated by analyzing the factor of merit and entropy generation performance. The results show that the SCD-MC with secondary channels and rib combinations enhance fluid disturbance and increase the solid-liquid contact area, significantly improving heat transfer. When Reynolds number (Re) is 586, compared with the straight microchannel, the average temperature at the bottom of the SCD-MC with rectangular secondary channels and rectangular rib (Case 5) is reduced by 4.8 K, the heat transfer coefficient is increased by 209.8 %, and the factor of merit is improved by 89.2 %. The entropy generation augmentation number of the Case 5 microchannel was the minimum of 0.52, which has the highest energy saving effect. The factor of merit of the Case 5 microchannel exhibits a tendency to first increase and then decrease with the increase of the relative width of the secondary channel (Psi), the relative width of the rib (Phi), and the relative position of the rib (Pi). At Re = 586, Psi = 0.933, Phi = 0.667, and Pi = 0.5, the factor of merit of the Case 5 microchannel is 2.08, indicating the highest comprehensive performance. This finding provides new ideas and methods for the design and application of microchannel thermal management.