中文摘要：

用高速摄像仪对过冷沸腾中的汽泡行为进行了可视化研究，发现在窄空间内，汽化核心密度与热流密度的关系和常规流道的一样，随着热流密度的增加而增加，且汽化核心密度仍与热流密度的平方成正比例关系；窄通道内质量流速对汽化核心密度的大小几乎没有影响，只对沸腾起始点有影响；在同样的热流密度条件下，流道间隙越小，汽化核心密度越大。且随着热流密度的增加，流道间隙对汽化核心密度的影响越大。

英文摘要：

At present work, visualized subcooled flow boiling experiments were conducted using a flat stainless steel surface heater. Results indicate that the active nucleation site density of narrow channel is with the same tendency as the regular channels, which is proportioned to the heat flux. Mass flux is with little ef- fect on the active nucleation site density of channel, but with effect on the onset of nucleate boiling. With the same heat flux, the narrower the channel, the highter the active nucleation site density. The effect of channel width on the active nucleation site density increases with the increasing of the heat flux.