关键词: 倾斜射流, 液膜, 射流撞壁, 液膜铺展, 网格自适应加密

Abstract:

In order to deepen the understanding of the liquid film formed by the spreading of the jet impinging onto the plate， the numerical simulation of the oblique jet impinging onto the wall was carried out in this paper. The two-phase numerical simulation of the liquid film spreading process after the jet impinge onto the wall was carried out using mesh adaptive method. The spreading process， flow field structure and local flow characteristics of the wall impingement zone were obtained and analyzed under typical working conditions. The key characteristics of the liquid film can be clearly identified from numerical simulation results， and the comparison with the experimental results also shows the feasibility and accuracy of the numerical simulation method. Through numerical simulation， it is found that after the jet impinges onto the wall， the flow takes the stagnation point as the center and spreads around in a radial structure. After merging into the hydraulic-jump zone at the edge of the liquid film， the flow direction deflects and continues to flow downstream. This is the basic process of the jet impinging the wall and spreading to form the liquid sheet. Inertial force drives the liquid film to radiate outward and spread out. Then， under the influence of the surface tension and surface contact angle at the edge of the liquid film， a high pressure zone of the liquid film is formed and pushes the liquid film to shrink. The inertia force of the liquid film decreases gradually under the shear action of the wall until it is in balance with other forces such as the surface tension at the edge of the liquid film. Thus， the boundary of the liquid film is determined. The numerical simulation results also verify that the stagnation point of the flow in the impingement zone is near a focal point of the elliptical contact surface between the jet and the wall.

Key words: oblique jet, liquid film, jet impinging onto a wall, spread of liquid film, mesh adaptive method