中文摘要：

针对水在垂直矩形通道内的流动沸腾，对空穴核化的机理进行了实验研究。不同表面物性的沸腾对比发现良好湿润性表面成核更为持续稳定。空穴成核过程中形成的低过热区域超出了气泡直径大小，影响因数在1．3-1．8范围内变化。微液膜蒸发模型分析液膜厚度在活化核心处最小，而热流密度刚好相反。流动条件加强了气泡脱离运动，致使主流对流冷却作用增强，影响范围超出了气泡直径区域。核心间的相互作用导致核心状态出现间断性，同时主流对流冷却也是重要原因。

英文摘要：

An experiment was conducted to investigate the nucleation mechanism of flow boiling in an upwards rectangular channel. The good wettability surface can create more continuous and stable nucleation based on the experimental boiling phenomena at the different surfaces. A low superheat wall temperature area occurs during the nucleating, and it is larger than the bubble radius. The radio of the superheat area and the projected bubble area ranges between 1.3 and 1.8. With the microlayer evaporation model, it is concluded that the microlayer thickness is the least at the nucleation site and the heat flux density is just reverse. The flow enhances bubble deviation and convection cooling effect, which results in the low superheat area exceeds the bubble diameter. The non-linear interaction among nucleated cavities and the convection cooling of main flow cause the discontinuity of nucleation.