竖直矩形窄缝通道内过冷沸腾传热特性的实验研究

Experimental Study on Heat Transfer Characteristics of Subcooled Flow Boiling in a Narrow Vertical Rectangular Channel

以去离子水为工质,在进口压力为0.1~0.3 MPa、质量流速为200~1400 kg·m^-2·s^-1、热流密度为20~320k W·m^-2的参数范围内,对截面参数为50mm×2mm的竖直矩形窄缝通道展开了传热实验研究。实验获得通道内部工质由单相状态到过冷沸腾状态的传热过程曲线,将过冷沸腾段实验值与8个经验公式提供的预测值进行了对比与分析,采用相似原理以及回归分析法,建立了适用于竖直矩形窄缝通道的过冷沸腾准则关系式。研究结果表明,在竖直矩形窄缝通道内,热流密度对过冷沸腾传热具有主导作用;对于本实验的窄缝通道,Bertsch传热公式对于过冷沸腾段的预测效果相较于其他公式更好,本研究所建立的准则关系式与实验数据符合良好。因此,本研究建立的公式能够用于竖直矩形窄缝通道过冷沸腾传热系数的预测。

Experimental investigation on the heat transfer characteristics of the deionized water flow was performed in a narrow vertical rectangular channel. The cross-sectional dimension of the flow is 50 mm×2 mm. The experiments were performed with pressures at the inlet of the test section ranges from 0.1 to 0.3 MPa, mass flux ranges from 200 to 1400 kg·m^-2·s^-1, and heat flux ranges from 20 to 320 kW·m^-2. The boiling curves and the heat transfer curves of water were obtained in narrow rectangular channel. Compared with 8 empirical correlations separately, and adopting similar theories and regression analysis, a new correlation is proposed for the narrow vertical rectangular channel in the subcooled flow boiling region. The study results show that in the narrow vertical rectangular channel, the heat flux shows the major enhancement effect as subcooled flow boiling happens, the Bertsch correlation predicts the experimental data best among those empirical correlations, and the new correlation predicts the experimental data well. Thus, the new correlation used in the paper is applicable in the prediction of the heat transfer coefficient of subcooled flow boiling in the narrow vertical rectangular channel.