Micro/nanoscale surface on enhancing the microchannel flow boiling performance: A Lattice Boltzmann simulation

•1. A novel LBM model for microchannel heat sink design is developed.•2. Effects of wettability and micropillar on heat transfer enhancement are discussed.•3. A geometric factor is introduced, and optimum pillar structures are proposed.•4. Biphilic micropillar surfaces achieve excellent overall thermal performance. Microchannel Heat Sink (MCHS) has been widely adopted in thermal engineering fields, such as refrigerators, chip cooling, battery packs, etc. To meet the ever-increasing demand for heat dissipation, surface modification methods adopting micro/nanoscale-modified surfaces have received considerable attention. In this paper, an advanced micro/nanoscale surface modification design is proposed based on a Lattice Boltzmann method (LBM) simulation study. Coupled boundary treatments at the inlet/outlet are developed with better numerical stability. The effects of surface wettability and micropillar on MCHS heat transfer performance are analyzed through bubbles' dynamic behaviors, Nusselt number, heat flux, and pressure drop. Design-based suggestions are proposed, and the enhancement mechanisms are explained. Results show that hydrophobic surface is more preferred for temperature-sensitive devices with low superheat requirement (Ja