Hydrodynamics in Falling Liquid Films on Surfaces with Complex Geometry

The paper present the results of experimental studies on dynamics of the film flow of cryogenic liquid over the complex surfaces: vertical plane and ribbed aluminum plates with horizontal wave microtexture. Experimental results were obtained at the flow of liquid nitrogen. According to high-speed video recording, in case of horizontal microstructure the wave dynamics influences considerably liquid redistribution in transverse direction. This is caused by the fact that liquid flows intensively at propagation of secondary waves along the channels of horizontal microstructure. According to results of experiments on the ribbed structured perforated aluminum surfaces with the horizontal microstructure with the use of highly wetting low-viscous liquids, the film flow character depends significantly on the irrigation rate. The direction and parameters of microstructure, position and diameter of holes effect significantly the zones of liquid spreading and its distribution over the surface of the ribbed structured plates, especially, within the range of low liquid flow rates.