Semi-empirical model for the liquid fuel film formed by an oblique jet impinging on a curved wall

Abstract

The operating conditions and the properties of the liquid have great effects on the shape and size of the liquid film and eventually affect the efficiencies of the atomization of alternative fuels, liquid jet impingement cooling, and equipment cleaning processes. The shape and size of the liquid film are dominated by the distance from the stagnation point to the liquid film edge(rmax). In this study, after deducing the thickness profile and the theoretical rather than the numerical solution of the initial velocity profile of the liquid film, a set of semi-empirical models about the shape, size of the liquid film, and the width of the raised zone formed by an oblique jet impinging on curved walls have been developed. In order to validate the theoretical model, a corresponding experiment has been developed, in which the jet velocities, impingement angles, liquid viscosity, surface tension, and radius of curvature have been included. The comparisons showed the theoretical results are in good agreement with the experimental data. The error for the location of the inner and outer border lines are less than 14.9% and 13.5%, respectively, except for the location in the upstream part of the film. And the effects of jet velocity, impingement angle, surface tension, dynamic viscosity, and radius of curvature were also theoretically discussed. The outer border line of the liquid film is dominated by the impingement angle and the impingement velocity, which affect the rmax exponentially and linearly, respectively. And the liquid viscosity and surface tension coefficient also affect the rmax approximately linearly. But the effects of the liquid viscosity and surface tension coefficient on the rmax are much less than the impingement velocity. The radius of curvature has little effect on the outer border lines and width of the raised zone when gravity is ignored.