Phase‐Field Numerical Investigation of Bubble Growth During Flow Boiling in a Corrugated Microchannel

Abstract

Flow boiling in corrugated microchannels offers considerable potential for high‐heat‐flux thermal management owing to the increased heat‐transfer area and enhanced interfacial transport induced by wall corrugations. In the present study, a phase‐field model is employed to numerically investigate vapor‐bubble growth, vapor‐slug evolution, and thermal‐hydraulic performance during flow boiling of water in a corrugated microchannel. Three operating conditions are investigated with wall temperatures of 378.15, 381.15, and 383.15 K, contact angles of , , and , inlet velocities of 0.073, 0.146, and 0.290 m/s, and surface‐tension coefficients of 0.0400, 0.0500, and 0.0589 N/m, respectively. The resulting interfacial dynamics, temperature field, volumetric mass‐transfer rate, pressure drop, heat‐transfer coefficient, Nusselt number, and thermal performance factor are systematically evaluated. The results reveal a progressive transition from a localized vapor embryo to an elongated vapor slug, governed by evaporation‐induced expansion, flow‐induced deformation, surface tension, and channel confinement. Under the investigated operating conditions, increasing wall temperature and inlet velocity accelerates vapor‐slug development and enhances thermal transport, whereas increasing the contact angle reduces liquid spreading and localizes evaporation near the wall‐adjacent liquid–vapor interface. Quantitatively, the heat‐transfer coefficient increases from approximately to , corresponding to an enhancement of approximately 139%. The thermal performance factor increases from 1.00 to 1.33 and 1.53, yielding a maximum improvement of 53%. Although the pressure drop increases with Reynolds number and vapor‐slug development, the improvement in heat‐transfer performance outweighs the associated hydraulic penalty. These results demonstrate that the coupled effects of wall corrugation, operating conditions, wettability, and interfacial properties strongly influence vapor‐slug dynamics and the resulting thermal‐hydraulic performance of microchannel flow boiling. The findings provide physical insight into the interaction between corrugation‐induced flow disturbance, phase‐change dynamics, and wettability, and offer guidance for the design of compact thermal management systems, including high‐power electronic cooling, battery thermal management, fuel‐cell cooling, and other phase‐change cooling applications.