Performance evaluation of commonly used impaction substrates under various loading conditions
Performance evaluation of commonly used impaction substrates under various loading conditions
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DOI：
10.1016/j.jaerosci.2004.11.006
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发表时间：
2005-07-01
影响因子：
4.5
通讯作者：
Koutrakis, P
中科院分区：
文献类型：
--
作者：
Lee, SJ;Demokritou, P;Koutrakis, P
对未涂覆金属板、聚四氟乙烯膜过滤器、涂油金属板、涂油烧结多孔金属和聚氨酯泡沫塑料等常用冲击基材在不同载荷条件下的性能进行了系统评价试验。采用单级冲击器和由多分散玻璃微珠组成的人工气溶胶对衬底进行了测试。在非常低的载荷条件下，对于大于冲击器切割点（d(50)）的颗粒，未涂层金属板和特氟龙过滤基板都观察到明显的颗粒反弹。颗粒弹跳随着颗粒载荷的增加而减小，直到在加载质量约为3mg时达到平稳状态。还观察到收集效率曲线的移位，包括未涂覆金属和聚四氟乙烯过滤器的d（50）下降。尽管对大于d（50）的颗粒的收集效率仍然很高（95%），并且在涂油和涂油烧结金属上的收集质量保持在约30 mg（表明颗粒反弹和再夹带最小），但也观察到d（50）的降低。然而，对于加脂和加油的烧结金属基板，收集效率曲线随载荷增加的变化和随之而来的d（50）的下降是显著的，而对于PUF基板，既没有观察到明显的颗粒反弹，也没有观察到收集效率的显著变化。对于PUF，对于大于d（50）的颗粒，在高达30 mg的收集质量下，收集效率仍然很高（98%）。在PUF上d（50）的变化明显小于在平面和刚性基底上的变化。这些结果全面证实了冲击衬底的性质对传统惯性冲击器的颗粒弹跳和颗粒分离性能有显著影响。(c) 2004 Elsevier Ltd.版权所有。
This paper presents the results from the systematic performance evaluation tests of commonly used impaction substrates including uncoated metal plate, teflon membrane filter, greased metal plate, oiled sintered porous metal, and polyurethane foam (PUF), at various loading conditions. A single stage impactor and artificially generated aerosol composed of polydisperse glass beads were used to test the substrates. Significant particle bounce was observed for both the uncoated metal plate and Teflon filter substrate for particles larger than the impactor cutpoints (d(50)) at very low loading conditions. Particle bounce decreased with increasing particle loading until it reaches a plateau at a loaded mass of approximately 3 mg. A shift of collection efficiency curve was also observed, including a decrease of d(50) for both the uncoated metal and the teflon filter. Despite the fact that the collection efficiency for particles larger than d(50) remained high (95%) and constant up to about 30 mg of collected mass on the greased and the oiled sintered metal, an indication for minimum particle bounce and re-entrainment, a decrease of the d(50) was also observed. However, while the changes in collection efficiency curve with increased loading and the consequent decreases of d(50) were significant for the greased and oiled sintered metal substrate, for the PUF substrate, neither substantial particle-bounce nor significant changes in collection efficiency were observed. For PUF, the collection efficiency remained high (98%) for particles larger than the d(50) for upto 30 mg of collected mass. The changes of the d(50) on PUF are considerably less than those for the flat and rigid substrates. These results comprise a comprehensive confirmation that the nature of the impaction substrate has a significant effect on the particle bounce and particle separation performance of conventional inertial impactors. (c) 2004 Elsevier Ltd. All rights reserved.