Marangoni效应对降膜过程液体分布的影响

Influence of Marangoni effect on the liquid distribution of falling liquid films

采用红外热成像技术测量液膜表面温度分布和流动区域,确定液膜在固体壁面上的润湿面积,以分析液体在设备内的分布性能以及液膜表面的温度梯度,进而明确温度分布与液体分布之间的相互影响关系.实验发现液膜径向温度梯度引起的表面张力梯度,造成径向Marangoni流,影响液膜在固体壁面上的分布.在Marangoni效应的作用下,加热(冷却)能够减小(扩大)液体在固体壁面上的润湿面积.正体系(冷却降膜)中,流量能够促进温度梯度造成的Marangoni效应,而在负体系(受热降膜)中,较大的流量抑制了Marangoni效应.

By using infrared imaging technique, the flow characteristics and temperature distribution of the falling liquid film could be obtained, This makes it very convenient to determine the relationship between the flow and temperature distributions. It is found that heating （cooling） makes the film contracted （extended）, increasing （decreasing） the area of the film, due to the existence of lateral temperature gradient and so-caused Marangoni effect. For the positive system （cooled films）, liquid flow reinforces Marangoni effect is induced by temperature gradient, while larger liquid flow retards Marangoni effect in the negative system （heated films）.