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Diffusional Transfer Function for the Scanning Electrical Mobility Spectrometer (SEMS)
Aerosol Science and Technology ( IF 2.8 ) Pub Date : 2020-05-21 , DOI: 10.1080/02786826.2020.1760199
Yuanlong Huang 1 , John H. Seinfeld 1 , Richard C. Flagan 1
Affiliation  

Abstract The scanning electrical mobility spectrometer (SEMS), or scanning mobility particle sizer (SMPS), uses the differential mobility analyzer (DMA) operated in scanning mode to measure particle size distribution rapidly. To obtain the actual size distribution, the real-time transfer function (transmission efficiency of particles of different mobilities) is necessary, which has previously been investigated with numerical simulations or semi-analytical calculations. We present here a rigorous derivation of the diffusional DMA transfer function for an increasing-voltage scan based on analytically resolving particle trajectories between the instrument inlet and the outlet. This requires a 2D integration in the inlet and outlet space over the contour plot of the particle mobility distribution that can successfully transmit through the scanning DMA. For the first time, we show that the up-scan DMA transfer function for non-diffusive particles is trapezoidal (instead of triangular). The key parameter that determines the shape of the scanning DMA transfer function is the ratio of the characteristic scanning time to the average residence time, which yields the same transfer function as that for the static DMA when the ratio gets sufficiently large. The effect of particle diffusion is included via an extended outlet. The dimensionless equations for the trajectories and the method presented here can be generalized to the column DMA of any geometry. Copyright © 2020 American Association for Aerosol Research

中文翻译:

扫描电迁移谱仪 (SEMS) 的扩散传递函数

摘要 扫描电迁移谱仪(SEMS)或扫描迁移率粒度仪(SMPS)使用差动迁移率分析仪(DMA)在扫描模式下快速测量粒度分布。为了获得实际的尺寸分布,实时传递函数(不同迁移率的粒子的传输效率)是必要的,之前已经通过数值模拟或半解析计算进行了研究。我们在这里提出了基于分析解析仪器入口和出口之间的粒子轨迹的递增电压扫描的扩散 DMA 传递函数的严格推导。这需要在粒子迁移率分布的等高线图上的入口和出口空间中进行二维集成,可以成功地通过扫描 DMA 传输。我们第一次展示了非扩散粒子的向上扫描 DMA 传递函数是梯形(而不是三角形)。决定扫描 DMA 传递函数形状的关键参数是特征扫描时间与平均停留时间的比值,当该比值足够大时,它产生与静态 DMA 相同的传递函数。粒子扩散的影响是通过一个扩展的出口来实现的。轨迹的无量纲方程和这里介绍的方法可以推广到任何几何形状的柱 DMA。版权所有 © 2020 美国气溶胶研究协会 决定扫描 DMA 传递函数形状的关键参数是特征扫描时间与平均停留时间的比值,当该比值足够大时,它产生与静态 DMA 相同的传递函数。粒子扩散的影响通过一个扩展的出口被包括在内。轨迹的无量纲方程和这里介绍的方法可以推广到任何几何形状的柱 DMA。版权所有 © 2020 美国气溶胶研究协会 决定扫描 DMA 传递函数形状的关键参数是特征扫描时间与平均停留时间的比值,当该比值足够大时,它产生与静态 DMA 相同的传递函数。粒子扩散的影响是通过一个扩展的出口来实现的。轨迹的无量纲方程和这里介绍的方法可以推广到任何几何形状的柱 DMA。版权所有 © 2020 美国气溶胶研究协会 轨迹的无量纲方程和这里介绍的方法可以推广到任何几何形状的柱 DMA。版权所有 © 2020 美国气溶胶研究协会 轨迹的无量纲方程和这里介绍的方法可以推广到任何几何形状的柱 DMA。版权所有 © 2020 美国气溶胶研究协会
更新日期:2020-05-21
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