ScholarWorks@성균관대학교

초록

Developing cooling technologies for high-heat-flux electronics is essential for next-generation thermal management. Although jet impingement boiling and hybrid configurations that couple impinging jets with channel flow have been reported, subcooled boiling data and predictive correlations for estimating heat transfer performance in confined hybrid geometries remain limited. This study examines FC-72 subcooled flow boiling in a confined jet array impingement configuration integrated with channel flow. The test section consists of a channel with 11 inline jet holes and two side outlets. Boiling curves and the corresponding average heat transfer coefficient curves are obtained up to the critical heat flux for jet velocities of 2.0-7.0 m/s and inlet subcooling temperatures of 10-30 degrees C, accompanied by synchronized high-speed visualization. The critical heat flux increases with jet velocity and inlet subcooling, reaching 169.2 W/cm 2 at a jet velocity of 7.0 m/s and an inlet subcooling of 30 degrees C, while the peak average heat transfer coefficient reaches 35,966 W/m 2 K at a jet velocity of 7.0 m/s and an inlet subcooling of 10 degrees C. Visualization shows that vapor blankets initiate near the outlet-side downstream region at elevated heat flux and expand toward the channel midpoint at the critical heat flux, restricting liquid access to the heated surface and reducing the average heat transfer coefficient. Finally, a new correlation for the average Nusselt number is developed from 144 two-phase data points using the Reynolds number, boiling number, modified Jakob number, and Prandtl number, and its applicability is assessed using previous datasets across multiple working fluids and configurations.

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