CFD Analysis of Internal Flow Characteristics between Hypervapotron Fin Slots under Flow Boiling

This study develops a two-dimensional CFD framework to analyze internal flow and boiling behavior in hypervapotron structures. The model couples an interfacial heat transfer approach with an extended RPI wall boiling model to capture vortex-induced phase-change phenomena. Grid sensitivity analysis identified a 250 μm mesh (y⁺≈40) as optimal, resolving key vortex structures and providing stable thermal gradients without numerical artifacts. In single-fin simulations, boiling initiated at t≈0.5 s, and the primary vortex soon dominated bubble transport, replicating the “vapotron effect” of vapor ejection and liquid replenishment. Array simulations showed that low heat flux (1 MW/m²) supported stable cooling, while high heat flux (2 MW/m²) induced vapor film formation and bubble accumulation. These findings underscore the importance of combined boiling models and mesh resolution for accurate thermal analysis of ultra high heat-flux cooling systems, such as hypervapotron.