激波诱导高速气流中液滴的初期变形

发布时间：2018-03-25 12:42

本文选题：液滴　切入点：破碎　出处：《爆炸与冲击》2017年05期

【摘要】：基于激波管平台和高速摄影方法对平面激波诱导高速气流中液滴的早期变形现象进行实验研究。研究发现在相近的We数或Re数下,实验参数的改变可导致液滴形态发展出现显著差异。这种差异主要体现在背风面的脊状环形突起、褶皱区以及后驻点区的凹凸形态。对刚性圆球外流的数值模拟显示,液滴变形早期形态与外流场结构和表面气动力分布之间存在鲜明的对应关系。最后采用简化理论推导出一组估测液滴早期变形的表达式。将数值模拟所得气动力数据代入计算发现:导致液滴变形的主要驱动力是液滴表面不均匀压力的挤压效应,而不是界面剪切摩擦所引起的切向流动堆积效应,前者高出后者约2个数量级;此外,采用压力作用理论计算所得液滴外形在主要变形特征和变形量级上均可与实验图像很好地吻合。
[Abstract]:Based on shock tube platform and high speed photography method, the early deformation of droplets in high velocity airflow induced by plane shock wave is studied experimentally. It is found that under the similar numbers of We or re, The change of experimental parameters can lead to significant difference in droplet morphology development, which is mainly reflected in the shape of ridge annular protuberance, fold region and posterior static point region of leeward surface. The numerical simulation of rigid sphere outflow shows that, There is a distinct correspondence between the early morphology of droplet deformation and the structure of the outflow field and the distribution of aerodynamic forces on the surface. Finally, a set of expressions for estimating the early deformation of droplets are derived by using the simplified theory, and the aerodynamic forces obtained by numerical simulation are obtained. It is found that the main driving force leading to droplet deformation is the extrusion effect of uneven pressure on the droplet surface. The piling effect of tangential flow caused by interfacial shear friction is about two orders of magnitude higher than that of the latter. The shape of the droplet calculated by the pressure action theory is in good agreement with the experimental images in terms of the main deformation characteristics and the magnitude of deformation.
【作者单位】：中国科学技术大学近代力学系;
【基金】：国家自然科学基金项目(11102204,11572313)
【分类号】：O35

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