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微结构表面核化沸腾初始气泡特征的微观观测* |
Microscopic Observation of Initial Bubbles in Nucleate Boiling on Microstructured Surfaces |
投稿时间:2022-05-07 修订日期:2022-06-28 |
DOI: |
中文关键词: 池沸腾 微结构 气泡初始温度 动态过程 |
英文关键词:nucleate boiling microstructure onset of nucleate boiling dynamic process |
基金项目:合肥大科学中心协同创新培养基金 |
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中文摘要: |
沸腾传热特性明显高于单相传热,广泛应用于航空、航天、航海、电子、能源、动力、空调、制冷、生物医学等众多领域的相关系统和设备。沸腾传热中气化潜热可以带走大量热流,同时产生的气泡产生扰动,加强传热。初始气泡特征是影响核化沸腾传热特性重要因素,表面结构对初始气泡的生成具有十分重要的影响。表面结构改变液体沸腾过程中的沸腾初始点温度、气泡直径和气化核心密度等气泡特征参数,从而提高核化沸腾传热特性。制备了3种带有不同尺度微结构且比表面积相同的单晶硅片,搭建了一套核化沸腾可视化微观观测实验平台,观测气泡生长的动态过程。通过实验对比证实了微结构较光滑表面对气泡增长均有促进作用,且实验范围内微尺度越大效果越明显。 |
英文摘要: |
The heat transfer characteristics of nucleate boiling are significantly higher than that of single-phase heat transfer. Nucleate boiling widely used in related systems and equipment in many fields such as aviation, aerospace, navigation, electronics, energy, power, air conditioning, refrigeration, and biomedicine. The latent heat of vaporization in boiling heat transfer can take away a large amount of heat, and the bubbles create disturbance, which can enhance heat transfer. The initial bubble characteristics are an important factor affecting the heat transfer characteristics of nucleation boiling, and the surface structure on the heated wall has a very important influence on the formation of the initial bubbles. The surface structure can change the bubble characteristic parameters, such as the temperature of onset of nucleate boiling, bubble diameter, and nucleation site density, etc. Therefore, understanding of the bubble characteristic parameters on the structured surfaces is significant to the development of the enhanced boiling heat transfer mechanism. Three kinds of single crystal silicon wafers with different scale microstructures and the same specific surface area were prepared. A set of nucleation boiling visualization microscopic observation experimental platform to observe the dynamic process of bubble growth was built. The experimental results showed that the microstructure on the heating surface could promote the growth of bubbles and the effect might be associated with the structural scale. |
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