湿表面多入射角水滴撞击特性实验研究

An experimental investigation on impingement characteristics of droplets with various incidence angles impinging on wetted surface

  • 摘要: 对毫米级水滴多入射角撞击静置薄水膜的现象进行实验研究,综合分析了水滴撞击韦伯数、入射角度和相对水膜厚度对液冠特征参数及飞溅阈值的影响。研究表明:当水滴切向撞击韦伯数一定时,随着入射角度的增大,液冠高度增大,但液冠半径随无量纲时间演化的规律不受影响;当水滴法向撞击韦伯数一定时,液冠高度和液冠半径均随入射角度的减小而增大。随着相对水膜厚度增大,液冠顶部半径减小,液冠底部半径增大,液冠高度呈现先增大后降低的趋势。本文建立了预测模型以描述相对水膜厚度为0.1时的最大冠顶高度和液冠半径的时间演化结果,得到了相对水膜厚度为0.1和0.2时的飞溅阈值模型。

     

    Abstract: The phenomena of millimeter sized water droplets impinging on a thin stationary water film at multiple incidence angles are experimentally investigated in this work. The effects of water droplet impacting Weber number, incidence angle, and dimensionless water film thickness on crown characteristic parameters and splash threshold are comprehensively analyzed. The experimental results show that as the tangential impacting Weber number is constant, the height of the liquid crown increases with the increase of the incidence angle, but the evolution law of the liquid crown radius is independent. As the normal impacting Weber number is constant, the height and radius of the liquid crown increase with the decrease of the incidence angle. As the dimensionless water film thickness increases, the radius of the liquid crown top decreases, while the radius of the liquid crown bottom increases. The height of the liquid crown first increases and then decreases with the increasing dimensionless film thickness. The prediction models are summarized to describe the experimental results of the maximum liquid crown height and the evolution of the liquid crown radius over time when the dimensionless water film thickness is 0.1. The splash threshold models for the dimensionless water film thickness of 0.1 and 0.2 are also summarized, respectively.

     

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