Abstract A visualization study of the bubble behavior in pool boiling of ultra-pure water and surfactant aqueous solution (Triton X-114) under different heat fluxes was performed, using a narrow transparent bare FTO heating surface with various subcooling degrees of 5°C, 25°C and 35°C, respectively. It is shown that with the decrease of liquid subcooling, bubble coalescence in ultra-pure water becomes obvious. Whilst with the increase of liquid subcooling, the bubble surface gets rough and unstable. In contrast, a newly discovered phenomenon of bubble-bubble (BB) penetration occurs in the surfactant solution under the same working condition as that in water. BB penetration behavior is a bubble interaction without coalescence. This bubble behavior is believed to be the results of micro-convection due to the shrinkage of the bubble root, and the Marangoni effect due to the surface tension gradient. Combination of Marangoni effect and bubble surface movement causes the surfactant molecules to aggregate toward the bubble root, and it effectively promotes the nucleation of the next bubble. Owe to the rapid growth of newly nucleated bubbles, the bubble-bubble penetration and piercing behaviors happen during the growth stage. The newly nucleated bubble partially accelerates the first bubble departure, also interacts with the first bubble by forming a tiny vapor channel. This phenomenon should be one of the reasons of enhanced heat transfer using surfactant solutions.

中文翻译：

---

水和非离子表面活性剂水溶液中过冷池沸腾过程中的气泡行为

摘要 对不同热通量下超纯水和表面活性剂水溶液 (Triton X-114) 的池沸腾气泡行为进行了可视化研究，使用窄透明裸 FTO 加热面，不同过冷度为 5°C，分别为 25°C 和 35°C。结果表明，随着液体过冷度的降低，超纯水中的气泡聚结变得明显。随着液体过冷度的增加，气泡表面变得粗糙和不稳定。相比之下，在与水中相同的工作条件下，表面活性剂溶液中会出现新发现的气泡（BB）渗透现象。BB 渗透行为是一种没有聚结的气泡相互作用。这种气泡行为被认为是气泡根部收缩引起的微对流的结果，以及由于表面张力梯度引起的 Marangoni 效应。马兰戈尼效应和气泡表面运动的结合，使表面活性剂分子向气泡根部聚集，有效促进下一个气泡的成核。由于新成核气泡的快速增长，气泡的渗透和刺穿行为发生在生长阶段。新成核的气泡部分加速了第一个气泡的离开，还通过形成微小的蒸汽通道与第一个气泡相互作用。这种现象应该是使用表面活性剂溶液增强传热的原因之一。并且有效地促进了下一个气泡的成核。由于新成核气泡的快速增长，气泡的渗透和刺穿行为发生在生长阶段。新成核的气泡部分加速了第一个气泡的离开，还通过形成微小的蒸汽通道与第一个气泡相互作用。这种现象应该是使用表面活性剂溶液增强传热的原因之一。并且有效地促进了下一个气泡的成核。由于新成核气泡的快速增长，气泡的渗透和刺穿行为发生在生长阶段。新成核的气泡部分加速了第一个气泡的离开，还通过形成微小的蒸汽通道与第一个气泡相互作用。这种现象应该是使用表面活性剂溶液增强传热的原因之一。