中文摘要：

给出了在低热流密度、负压条件下有限小空间内沸腾凝结共存相变传热特性的实验研究结果。沸腾工质为去离子水，换热表面材料为紫铜，有限空间由加热铜柱的上表面和冷凝铜柱的下表面以及不锈钢圈的侧壁面构成，有限空间的高度为26mm，充液液面高度从10mm到16mm。实验观察和测试结果表明，沸腾和凝结之间存在明显的相互作用和影响，随着液面高度的增加，沸腾表面传热系数先增加后减小。对压力信号的标准偏差分析表明，随着热流密度的增加，压力波动的标准差均呈现先增大后趋于常数的趋势，表明气泡受到了有限空间的影响。实验结果还表明，存在一个使沸腾和凝结表面传热系数最大的充液高度，这为优化平板热管均热器等存在沸腾一凝结共存现象的装置的设计提供了参考。

英文摘要：

The experimental results of boiling and condensation co-existing phase change heat transfer characteristics in a small and vacuum confined space under low heat flux conditions are presented. The working medium used is de-ionized water, the heating and cooling surfaces are polished copper. The gap of the confined space is 26 mm, and the water level in the gap is set at 10 mm, 12 mm, 14 mm and 16mm, respectively. Experimental observation and results show that boiling and condensation processes are strongly inter-related and have significant influences over each other. As the water level increases, the boiling heat transfer coefficient increases at first and then decreases. Analysis of the standard deviations of the confined space pressure shows that as the heat flux increases, the pressure fluctuation increases first and then tends to maintain a constant. The experimental results also disclose that there exists an optimum water filling amount at which both the boiling and the condensation heat transfer coefficient acquire their maximum value.