浸没在多孔介质中的竖直管沸腾换热实验研究

EXPERIMENTAL STUDY OF POOL BOILING HEAT TRANSFER FROM A VERTICAL TUBE EMBEDDED IN A POROUS MEDIUM

本文对竖直管外填充固体颗粒情况下，蒸馏水和无水乙醇两种工质的池沸腾换热现象进行了实验研究，分析了颗粒直径以及工质热物性对竖直管液池沸腾换热特性，包括沸腾滞后的影响规律，证明了在填充固体颗粒条件下，竖直管的池沸腾换热可以得到一定程度的强化，在低热负荷区，强化效果尤为明显。大颗粒对沸腾滞后现象有较好的缓解作用。在高热负荷区，由于气膜的出现，沸腾机理将有所改变。

Pool boiling heat transfer phenomenon of distilled water and ethanol from a vertical tube embedded in a porous medium at atmospheric pressure was experimentally investigated.The effects of particle diameters and working media properties on the boiling heat transfer characteristics, including boiling hysteresis have been analyzed. Below the critical heat fluxes,the pool boiling heat transfer can be enhanced with porous medium, especially at low heat fluxes. At high heat fluxes, a vapour film appears, thus a qualitative change in the mechanism of boiling occours. Relatively large particles can mitigate boiling hysteresis greatly.