航空学报 > 2023, Vol. 44 Issue (4): 126428-126428   doi: 10.7527/S1000-6893.2021.26428

倾斜射流撞壁铺展的数值仿真

唐亮(), 王凯, 李文龙, 刘亚洲, 张波涛, 任孝文   

  1. 西安航天动力研究所 液体火箭发动机技术重点实验室,西安 710100
  • 收稿日期:2021-09-24 修回日期:2021-10-18 接受日期:2021-11-29 出版日期:2023-02-25 发布日期:2021-12-09
  • 通讯作者: 唐亮 E-mail:tang410632@163.com
  • 基金资助:
    国家自然科学基金(11502186)

Numerical simulation on spreading of oblique jet impinging onto a wall

Liang TANG(), Kai WANG, Wenlong LI, Yazhou LIU, Botao ZHANG, Xiaowen REN   

  1. Science and Technology on Liquid Rocket Engine Laboratory,Xi’an Aerospace Propulsion Institute,Xi’an 710100,China
  • Received:2021-09-24 Revised:2021-10-18 Accepted:2021-11-29 Online:2023-02-25 Published:2021-12-09
  • Contact: Liang TANG E-mail:tang410632@163.com
  • Supported by:
    National Natural Science Foundation of China(11502186)

摘要:

为了加深对射流撞壁铺展形成液膜的认识,开展倾斜射流撞壁数值仿真研究。采用网格自适应加密技术对射流撞壁后的液膜铺展过程开展两相数值仿真研究,获得并分析了典型工况下液膜铺展的过程、流场结构以及射流撞壁区局部流动特征。从数值仿真结果中能清晰地分辨出液膜的关键特征,与试验结果的对比也表明了数值仿真方法的可行性与准确性。通过数值仿真发现,射流撞壁后,流动以滞止点为中心,呈辐射状向四周铺展,汇入液膜边缘处水跃区后流动方向偏转,并继续向下游流动,这是射流撞壁铺展形成液膜的基本过程;液膜的惯性力驱动着液膜呈辐射状向外铺展,而在液膜边缘位置处的表面张力和壁面接触角的影响下,液膜边缘形成高压区推动液膜收缩,液膜惯性力在壁面的剪切作用下逐渐减小,直至减小到与液膜边缘处表面张力等其他作用力相平衡,从而确定液膜的边界;数值仿真结果也验证了撞壁区流动的滞止点处于射流与壁面的椭圆形接触面的一个焦点附近。

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

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