Basic Study on Advanced Heat Transfer Equipment by Applying Boiling Heat Transfer Enhancement Surface with Porous Structure

点击翻译按钮获取中文摘要

Forced convective boiling heat transfer characteristics in narrow rectangular channels, such as saturated boiling heat transfer coefficient, wall superheat at the boiling inception on start-up, and critical heat flux in subcooled boiling flows, were experimentally examined. In the saturated boiling experiments, it had been clarified that boiling behaviors were dominated by nucleate boiling for vapor quality up to 0. 6, and high heat transfer enhancement factor up to 11 could be obtained. However, for high quality condition, deterioration in heat transfer coefficient was observed for the coating, because the boiling mode was changed from nucleate boiling to liquid film vaporization. The wall superheat overshoot in a rapid heating assumed for the start-up, could be reduced 15 K by the coating. For subcooled boiling with the inlet subcooling of 40 K, the coating produced higher CHF than the smooth surface, because vapor bubbles on the coating were smaller than those on the smooth surface.