倾斜射流撞壁实验研究及液膜几何参数建模

Experimental study on oblique jet wall impingement and geometrical parameter modeling of liquid film

倾斜射流撞壁在液体火箭发动机液膜冷却、射流撞壁雾化等领域具有广泛的应用。为了研究倾斜射流撞击壁面后形成的液膜的关键特征,开展单股圆柱射流撞击壁面的实验研究。从实验中研究各射流参数对液膜外形的影响规律,继而开展理论建模,获取液膜外形的关键几何参数表达式。实验研究发现随着射流倾角增大,液膜长度减小而宽度增大,随着射流孔径和射流速度增大液膜长度和宽度均增大这一定性规律。理论分析得到了液膜最大宽度位置与液膜对称面的夹角近似等于射流倾角α,液膜的长宽比近似等于1+cotα。通过进一步分析得到液膜宽度、最大宽度距撞击点的距离、液膜长度这几个液膜关键参数的表达式。建立的液膜几何参数表达式预测结果与实验结果的误差均在20%以内。

Oblique jet wall impingement has a wide range of applications in multiple fields such as liquid film cooling of liquid rocket engines and atomization.To study the key characteristics of the liquid film formed by the oblique jet wall impingement,we conducted an experimental study on a single cylindrical jet impinging onto the wall.The effects of various jet parameters on the liquid film shape were studied in the experiments,and theoretical modeling research was carried out to obtain the key geometric parameter expressions of the liquid film shape.It is found that as the jet angle increases,the liquid film length decreases and the width increases.As the jet diameter and velocity increase respectively,the liquid film length and width increase.Through theoretical analysis,the angle between the maximum width position and the symmetry plane of the liquid film is approximately equal to the incident angleα,and the aspect ratio of the liquid film 1+cotα.Further analyses obtain the geometric parameter expressions of the liquid film shape such as the width,the length,and the distance between the maximum width and the impinging point.The errors between the prediction and the experimental results are within20%in the geometric parameter expressions established above.