论文标题
大型Stokes数字的单独和关节聚类特征，受到中等湍流的共同流动
Separate and joint clustering characteristics of large Stokes number sprays subjected to moderately turbulent co-flows
论文作者
论文摘要
通过实验研究了注入湍流的共同流中喷雾剂的单独和关节液滴，簇和空隙特征。进行液滴尺寸的同时MIE散射和干涉激光成像，以及单独的热丝动态测定法。使用零，一个或两个穿孔的板调节湍流的共流特性。基于泰勒长度尺度的雷诺数从10到38不等，基于Kolmogorov时间尺度估计的Stokes数量从3到25不等。结果表明，由Kolmogorov长度量表归一化的群集的平均长度尺度与Stokes数字线性差异。但是，平均空间长度尺度在整数长度尺度的阶面。结果表明，簇内部的液滴的数量密度大约是空隙中的液滴密度约10倍。簇和空隙中的液滴密度与总数密度的比率分别与测试条件无关，分别等于8.3和0.7。液滴直径和簇面积的关节概率密度函数表明，大多数簇中的直径最大的液滴是最可能的。有人认为，加强湍流扩大了共同流动中湍流尺寸的范围，该涡流尺寸允许在簇中容纳具有较大直径的液滴。结果对于旨在修改大型Stokes数量液滴的聚类特性的工程应用具有重要意义，这些液滴喷洒到湍流的co-Flows中。
Separate and joint droplets, clusters, and voids characteristics of sprays injected in a turbulent co-flow are investigated experimentally. Simultaneous Mie scattering and Interferometric Laser Imaging for Droplet Sizing along with separate hotwire anemometry are performed. The turbulent co-flow characteristics are adjusted using zero, one, or two perforated plates. The Taylor length scale-based Reynolds number varies from 10 to 38, and the Stokes number estimated based on the Kolmogorov time scale varies from 3 to 25. The results show that the mean length scale of the clusters normalized by the Kolmogorov length scale varies linearly with the Stokes number. However, the mean void length scale is on the order of the integral length scale. It is shown that the number density of the droplets inside the clusters is about 10 times larger than that in the voids. The ratios of the droplets number densities in the clusters and voids to the total number density are independent of the test conditions and equal 8.3 and 0.7, respectively. The joint probability density function of the droplets diameter and clusters area shows that the droplets with the most probable diameter are found in the majority of the clusters. It is argued that intensifying the turbulence broadens the range of turbulent eddy size in the co-flow which allows for accommodating droplets with a broad range of diameters in the clusters. The results are of significance for engineering applications that aim to modify the clustering characteristics of large Stokes number droplets sprayed into turbulent co-flows.
