PMMA低温表面液滴凝结过程的实验研究

Experimental study on condensation process of PMMA surface droplet at low temperature

为了解不同温度下有机玻璃(PMMA)表面蒸汽凝结相变、液滴生长以及传热的过程,对有机玻璃表面的液滴冷凝过程进行了可视化实验观测,将液滴的凝结形态、面积率、接触角及尺寸变化等参数进行了分析并绘制出变化曲线,发现蒸汽在有机玻璃表面凝结时可形成颗粒分明的珠状液滴,凝结时间越长液滴直径越大;底板温度越低,面积率越大,接触角越大。控制以上变量可以有效改善蒸汽凝结效果,有利于提高热量传递效率,为液滴相变(汽-液)特性和换热表面结霜除霜技术提供理论支持。

In order to understand that process of vapor condensation phase change, droplet growth and heat transfer on PMMA surface at different temperature, the condensation process of liquid droplets on the surface of PMMA was observed by visual experiment. The parameters such as the condensation form, the area ratio, the contact angle and the size change of the droplet were analyzed and the change curves were drawn. It was found that when steam condenses on the surface of the PMMA, it can form granular beaded droplets, the longer the setting time, the bigger the droplet diameter. The lower the bottom plate temperature, the larger the area ratio and the larger the contact angle. Controlling the above variables can effectively improve the steam condensation effect and heat transfer efficiency, and provide theoretical support for droplet phase change(vapor-liquid) characteristics and defrosting technology of heat exchange surface.