Wall Permeability Estimation in Automotive Particulate Filters
Wall Permeability Estimation in Automotive Particulate Filters
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DOI：
10.4271/2023-24-0110
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发表时间：
2023-08
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通讯作者：
Callum Samuels;R. Holtzman;S. Benjamin;S. Aleksandrova;T. Watling;H. Medina
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作者：
Callum Samuels;R. Holtzman;S. Benjamin;S. Aleksandrova;T. Watling;H. Medina
多孔壁渗透性是估算汽车微粒过滤器的关键性能指标--背压的关键因素之一。可以对当前的实验和分析过滤器模型进行校准以预测特定过滤器的渗透率。然而，它们不能提供一个可靠的估计渗透率的关键参数，如壁孔率和孔径大小，这项研究提供了一种新的方法，以实验测定渗透性的滤墙。将四种不同孔隙率和孔径的基质的结果与几种流行的渗透率估计方法(实验和分析)进行了比较，并评估了它们在这一应用中的有效性。结果表明，无论是冷流还是热流，这些评估方法都不能预测所有基材的所有渗透率趋势，这表明除了孔隙率和孔径之外，其他壁面特性也很重要。热流测试结果表明，渗透率随着温度的升高而增加，这归因于滑移流动的影响。结果表明，滑移效应的大小也随滤壁性质的不同而变化。对现有的解释滑移影响的模型进行了评估，结果表明，对所有四种底物的影响都被大大低估了。在渗透率随温度增加是理想效果的应用中，这对于预测穿透损失很重要。需要进一步的研究来考虑高温对排气应用的影响。
Porous wall permeability is one of the most critical factors for the estimation of backpressure, a key performance indicator in automotive particulate filters. Current experimental and analytical filter models could be calibrated to predict the permeability of a specific filter. However, they fail to provide a reliable estimation for the dependence of the permeability on key parameters such as wall porosity and pore size.This study presents a novel methodology for experimentally determining the permeability of filter walls. The results from four substrates with different porosities and pore sizes are compared with several popular permeability estimation methods (experimental and analytical), and their validity for this application is assessed. It is shown that none of the assessed methods predict all permeability trends for all substrates, for cold or hot flow, indicating that other wall properties besides porosity and pore size are important.The hot flow test results show an increase in permeability with temperature, which is attributed to the effects associated with slip-flow. It is shown that the slip-effect magnitude also varies with the filter wall properties. Existing models that account for the effect of slip are assessed and are shown to underpredict the effect considerably for all four substrates. This is important for the prediction of through-wall losses in applications where permeability increase with temperature is a desirable effect. Further investigation is needed to consider the effect of the high temperatures in exhaust applications.