Factors affecting the diameter of ring-shaped deposition patterns in inertial impactors having small S/W ratios
Factors affecting the diameter of ring-shaped deposition patterns in inertial impactors having small S/W ratios
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DOI：
10.1080/02786826.2021.2007214
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发表时间：
2021-11-22
影响因子：
5.2
通讯作者：
Saylor, J. R.
中科院分区：
文献类型：
--
作者：
Kala, S.;Saylor, J. R.
惯性撞击器是气溶胶科学的重要组成部分，在广泛的实际和科学应用中，它们被用来获得颗粒尺寸分布。这些装置的缺点是，所得分布中的箱的数量限于冲击器级联中的冲击器的数量。最近的工作表明，如果喷嘴到冲击器的距离（S）与喷嘴直径（W）的比率非常小，S/W类似于O（0.01），则通常的盘形颗粒冲击图案变成环形。在这些条件下，环直径与颗粒直径成比例，这为开发能够进行子阶段颗粒直径测量的撞击器提供了机会。然而，在开发这种冲击器之前，需要进一步了解上述环的直径如何随S/W和颗粒直径变化。在此，提出了实验，其中获得了一系列的颗粒直径和S/W的环形沉积图案。这些结果被合并，以提供相关的无量纲变量之间的关系：斯托克斯数（无量纲颗粒直径），S/W，和无量纲环直径。在实验条件下的粒子轨迹的计算机模拟，并被用来揭示这种效果的潜在机制。最后，讨论了使用这些结果，以获得高分辨率的颗粒尺寸分布的撞击叶栅的实际方法。版权所有（c）2021美国气溶胶研究协会
Inertial impactors are an important part of aerosol science where they are used to obtain particle size distributions in a wide range of practical and scientific applications. A shortcoming of these devices is that the number of bins in the resulting distribution is limited to the number of impactors in an impactor cascade. Recent work has shown that if the ratio of the nozzle-to-impactor distance (S) to the nozzle diameter (W) is very small, S/W similar to O(0.01), the normally disk shaped particle impaction pattern becomes a ring. Under these conditions the ring diameter is proportional to the particle diameter, presenting an opportunity for developing impactors capable of sub-stage particle diameter sizing. Before such impactors may be developed, however, further information is required regarding how the diameter of the aforementioned rings vary with S/W and particle diameter. Herein, experiments are presented where ring-shaped deposition patterns are obtained for a range of particle diameters and S/W. These results are consolidated to provide a relationship between the relevant dimensionless variables: the Stokes number (dimensionless particle diameter), S/W, and dimensionless ring diameter. Computer simulations of particle trajectories under the experimental conditions are presented and are used to reveal the underlying mechanism of this effect. Finally, a discussion is presented of practical approaches for using these results to obtain high resolution particle size distributions from impactor cascades. Copyright (c) 2021 American Association for Aerosol Research