倾斜射流撞壁形成的液膜外形的理论建模

Theoretical Modeling of Liquid Sheet Shape Formed by Oblique Jet Impinging onto Wall

关键词:  倾斜射流撞壁  液膜  理论模型  接触角  液膜冷却

Key words:  Oblique jet impinging on the wall  Liquid sheet  Theoretical method  Contact angle  Liquid film cooling

摘要:

倾斜射流撞击壁面在燃烧室液膜冷却、溅板式喷注器雾化等领域均有广泛应用。为了研究倾斜射流撞壁形成的液膜的基本形态、液膜边界大小，开展理论建模研究。通过建立在液膜边界的守恒方程及液膜在壁面上的厚度及速度分布关联式，形成一套能够求解倾斜射流撞击壁面后液膜形态及边界的理论方法。模型计算结果与文献中的实验结果对比表明，建立的模型能够较为准确地反映出壁面上液膜的基本外形。理论模型计算表明：液膜铺展面积随着射流速度和射流直径的增大而增大；当射流与壁面的夹角增大时，液膜流量分布的改变会导致液膜长度减小，宽度增大；模型计算结果能够反映出液膜边界随接触角增大而变小这一定性规律。

Abstract:

The oblique jet impinging on the wall has a wide range of applications in the field of liquid film cooling in the combustion and atomization of spark injector. In order to study the basic shape， liquid sheet size and the boundary of the liquid sheet formed by the oblique jet impinging on the wall， theoretical modeling studies were carried out. By establishing conservation equations at the boundary of the liquid sheet and the expression of the thickness and velocity distribution of the liquid sheet on the wall， theoretical method for solving the shape and boundary of the liquid sheet formed by the oblique jet impinging on the wall was established. The comparison between the calculation results of the model and the experimental results in the literature shows that the established model can accurately reflect the basic shape of the liquid sheet on the wall. The calculation results show that the liquid sheet spreading area increases with the jet velocity and the jet diameter. When the angle between the jet and the wall increases， the change in the flow distribution causes the liquid sheet length to decrease and the width to increase. The model calculation results can qualitatively reflect that the liquid film boundary becomes smaller with increasing contact angle.