Influence of the Wetted Surface Curvature on the Laminar Liquid Film Thickness

Abstract

Liquid films flowing down vertical surfaces under the influence of gravity are encountered in many types of heat and mass transfer equipment consisting of vertical tubes and vertical plane surfaces. Therefore, a complete understanding of liquid film flow on vertical surfaces from the entrance to the exit should be of interest industrially and academically. The main reason for that is the influence exerted by the surface cross curvature and the film itself on heat transfer characteristics on the surface, transverse shear stress distribution, and correspondingly the thickness of the liquid film. This paper presents the evaluation of the surface cross curvature on the hydromechanical parameters of a laminar liquid film. The cross curvature of a wetted surface and the film alter the hydromechanical parameters of the liquid film. Simultaneously, the intensity of heat exchange between the wetted surface and liquid film is altered. Calculations evaluating velocity distribution across water and transformer oil film and correspondingly the thickness of the film were performed.