射流液滴撞击壁面二次液滴的粒径特性研究

Secondary droplet size formed by jet impact on small solid surface

液滴碰撞是液滴动力学研究的基本内容。基于可视化图像技术对射流液滴连续撞击微小固体壁面后形成的二次破碎飞溅液滴的粒径特性进行了实验研究,在低压低射流量的基础上,阐明了射流液滴连续撞击固体壁面破碎飞溅的雾化过程,分析了不同位置和驱动压力对二次破碎飞溅液滴粒径分布特性的影响,结果表明:二次液滴粒径总体而言相对较小,几乎位于100μm以下,且峰值区域基本集中在30~40μm之间,具有较好撞击雾化效应。二次液滴粒径在空间分布上存在差异,并非完全对称于撞击中心分布,水平方向上距离撞击点越远,二次液滴粒径越小;垂直方向上高度越高,粒径越小。随着驱动压力的增大,频率分布峰值的二次液滴粒径变小,二次液滴粒径分布范围变大。

Droplet collision is the basic content of droplet dynamics research.Based on the visualization image technology,the particle size characteristics of the secondary broken splash droplets formed after the jet droplets continuously hit the tiny solid wall are experimentally studied.The atomization process of the continuous impact of jet droplets on the solid wall crushing splash is clarified.And the influence of different positions and driving pressures on the particle size distribution characteristics of secondary crushing droplets is analyzed.Experimental results show that the particle size of secondary droplets is relatively small overall,almost below 100μm.And the peak area is basically concentrated between 30~40μm,which has a good impact atomization effect.The particle size of the secondary droplet differs in spatial distribution,is not completely symmetrical to the center of impact,e.g.,the farther away from the impact point in the horizontal direction,the smaller the particle size of the secondary droplet;the higher the height in the vertical direction,the smaller the particle size.As the driving pressure increases,the particle size of the secondary droplet at the peak of the frequency distribution becomes smaller,and the particle size distribution range of the secondary droplet becomes larger.