功能表面材料与流体界面相互作用对垂直降液膜流动特性的影响

Impact of the Interaction between Solid Surfaces and Liquid on the Flow Characteristics of Vertically Falling Liquid Film

通过调节水温度、添加表面活性剂以及铝合金壁面表面改性处理来改变降膜流体与固体表面之间的表面自由能差值,运用JDC-2000型精密测微仪测定垂直降液膜的厚度,研究固体表面和液体间相互作用对流体垂直降膜流动特性的影响;考察了液膜雷诺数、流体温度、添加表面活性剂、固体表面材料物理化学性质等因素对垂直壁面降液膜流动特性的影响规律。实验结果表明:改变固体表面与降液膜流体的物理化学特性,即改变固液界面的相互作用能够改变流体的降膜流动特性。降液膜平均厚度随液固表面自由能差的增大而减小。

The thickness of liquid film falling along a vertical plate was measured by using the JDC-2000 precise capacity micrometer. The effects of the liquid temperature, solid surface nature, and addition of surfactant were investigated experimentally in order to get insight to the effect of the interaction between the solid surfaces and water, i.e. the surface free energy difference of water and solid surface, which was adjusted by variation of the water temperature, modified surfaces and addition of surfactant. The effects of film Reynolds number, water temperature, physicochemical property of the specially modified surfaces and addition of surfactant on the thickness of falling film were examined and discussed. It was found that the average thickness of the falling liquid film decreased with the increase of the surface free energy difference of the solid and falling fluid.