Evaluation of the polyurethane foam (PUF) disk passive air sampler: Computational modeling and experimental measurements
Evaluation of the polyurethane foam (PUF) disk passive air sampler: Computational modeling and experimental measurements
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DOI：
10.1016/j.atmosenv.2011.05.052
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发表时间：
2011-08
影响因子：
5
通讯作者：
Andrew A. May;P. Ashman;Jiaoyan Huang;S. Dhaniyala;T. Holsen
中科院分区：
文献类型：
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作者：
Andrew A. May;P. Ashman;Jiaoyan Huang;S. Dhaniyala;T. Holsen
计算流体动力学 (CFD) 模拟与风洞实验相结合，用于确定广泛使用的聚氨酯泡沫 (PUF) 盘被动采样器的采样率 (SR)。在风洞实验中，通过测量随时间推移的重量损失来确定安装在采样器外壳中的水饱和 PUF 盘的水蒸发速率。此外，还使用了经过改进的被动采样器，设计用于通过镀金过滤器收集元素汞 (Hg0)。在不同的风速和不同的采样器角度下进行了实验。通过空气扩散率比例缩放值，将风洞实验获得的 SR 与现场获得的 SR 进行比较。三维 (3D) CFD 模拟也用于生成多氯联苯 (PCB) 和 Hg0 的 SR。总体而言，建模和测量的 SR 非常吻合，并且与现场研究获得的值一致。正如之前观察到的，SR 随着风速的增加而线性增加。此外，还确定 SR 强烈依赖于环境风的角度。当底座朝风向上倾斜时，SR 增加；当底座向下倾斜（即，采样器的顶部面向风）时，SR 首先减小，然后增加。结果表明，在不了解相对于采样器的风速和风角的情况下，从被动采样器测量获得的浓度可能存在显着的不确定性。
Computational fluid dynamics (CFD) simulations coupled with wind tunnel-experiments were used to determine the sampling rate (SR) of the widely used polyurethane foam (PUF) disk passive sampler. In the wind-tunnel experiments, water evaporation rates from a water saturated PUF disk installed in the sampler housing were determined by measuring weight loss over time. In addition, a modified passive sampler designed to collect elemental mercury (Hg0) with gold-coated filters was used. Experiments were carried out at different wind speeds and various sampler angles. The SRs obtained from wind-tunnel experiments were compared to those obtained from the field by scaling the values by the ratios of air diffusivities. Three-dimensional (3D) CFD simulations were also used to generate SRs for both polychlorinated biphenyls (PCBs) and Hg0. Overall, the modeled and measured SRs agree well and are consistent with the values obtained from field studies. As previously observed, the SRs increased linearly with increasing wind speed. In addition, it was determined that the SR was strongly dependent on the angle of the ambient wind. The SRs increased when the base was tilted up pointing into the wind and when the base was tilted down (i.e., such that the top of the sampler was facing the wind) the SR decreased initially and then increased. The results suggest that there may be significant uncertainty in concentrations obtained from passive sampler measurements without knowledge of wind speed and wind angle relative to the sampler.