混合工质Marangoni凝结换热过程的定量特性研究

The present project will investigate the Marangoni condensation process of mixture vapors, which is only effected by the surface tension gradients. The characteristic of heat transfer and the condensation modes will be studied systematacially by both theoretical and experimental methods. Using the experimental methods, the factors concerned condensation modes and their variation trends with the influencing factors will be studied. The characteristic of condensation heat transfer will be also measured. The characteristic of Marangoni condensation heat transfer and the influencing factors will be dealt with dimensionless method, and some dimensionless numbers will be presented to replace them. Based on the experimental data, the variation trends of the dimensionless heat transfer characteristic with the dimensionless influencing factors will be studied. Then the correlations of Marangoni condensation heat transfer for some typical mixture vapors will be obtained. Finally,a general theoretical calculation method will be presented, considering Marangoni condensation as both condensation of mixture vapors and Pseudo-dropwise condensation. The general characteristic of Marangoni condensation heat transfer will be analyzed, and the characteristic for common mixture vapors will be predicted. The project will help to understand Marangoni condensation, obtain the characteristic of heat transfer, and also provide the groundwork for the application of Marangoni condensation in heat exchangers. These works show great academic significance and applicable potential.

本项目采用理论与实验结合的方法对仅由表面张力梯度影响的混合工质Marangoni凝结换热特性及凝结形态进行系统深入的研究，通过实验研究获得定量描述凝结形态的参数及其随各影响因素的定量变化规律，同时测量计算得到凝结换热特性；提炼出能表征Marangoni凝结换热特性及其影响因素的无量纲准则数，对其进行无量纲化处理，结合实验数据研究各无量纲准则数之间的变化规律，获得具有代表性的混合工质Marangoni凝结换热特性定量计算关联式；最终建立能反映Marangoni凝结属于混合工质凝结同时具有类珠状凝结形态特点的通用的凝结换热理论计算方法，探求Marangoni凝结换热的一般定量变化规律，分析可形成Marangoni凝结的更大范围的混合工质的凝结换热特性。本项目将进一步认识Marangoni凝结现象，获得凝结换热特性，为在换热器中实现这种凝结奠定基础，具有重要的学术意义和实用价值。

本项目采用理论与实验结合的方法对仅由表面张力梯度影响的混合工质Marangoni 凝结过程开展了系统研究，提出了适合Marangoni凝结的凝结形态图像边缘提取方法，通过可视化研究获得了最大液珠半径、液珠尺寸分布等凝结形态表征参数的变化规律；测量得到了不同条件下的凝结瞬态换热特性和时均换热特性；对比获得了凝结表面曲率对Marangoni凝结换热特性的影响规律。针对Marangoni 凝结换热特点，提炼出了表征其换热特性及影响因素的无量纲准则数，基于实验数据得到了水-酒精混合蒸气Marangoni 凝结换热实验关联式。考虑具有正系统特性的混合蒸气凝结时形成类珠状凝结形态的特点，将其视为混合蒸气的珠状凝结，建立了混合蒸气Marangoni凝结换热特性理论计算模型，可预测不同过冷度、混合工质浓度、蒸气压力与流速等条件下的凝结换热特性。本项目将进一步认识Marangoni 凝结现象，获得凝结换热特性，为在换热器中实现这种凝结奠定基础，具有重要的学术意义和实用价值。