Modeling the Flow and Transport Dynamics in Gasoline Particulate Filters to Improve Filtration Efficiency
Modeling the Flow and Transport Dynamics in Gasoline Particulate Filters to Improve Filtration Efficiency
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DOI：
10.1115/1.4046151
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发表时间：
2020-03
期刊：
影响因子：
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通讯作者：
S. Korneev;S. Onori
中科院分区：
文献类型：
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作者：
S. Korneev;S. Onori
针对汽油颗粒过滤器(GPFS)中的流体流动和颗粒传输，提出了一种新的孔道模型或混合模型。GFP是一种排放控制装置，旨在去除汽油直喷式发动机排气系统中的微粒。在这项研究中，我们考虑了一种壁流无涂层GPF，它由一束由多孔壁隔开的入口和出口通道组成。充满颗粒的废气流入进气通道，穿过多孔壁，然后从出气通道流出。我们使用不可压缩的Navier-Stokes方程和空间平均的Navier-Stokes方程来模拟入口和出口通道内的流动。对于颗粒输运，采用耦合平流和空间平均对流-反应方程，其中反应项模拟颗粒的积累。利用OpenFOAM对流动方程和输运方程进行了数值求解，结果表明，沉积颗粒的浓度沿过滤器长度方向呈不均匀分布，随着雷诺数的增加，过滤器后端的沉积颗粒浓度增大。烟尘过滤器的X射线计算机层析(XCT)扫描实验图像表明，这种不均匀分布与模型预测的结果是一致的。最后，我们展示了如何使用所提出的模型来优化过滤器设计以提高过滤效率。
We propose a new pore-scale/channel model, or hybrid model, for the fluid flow and particulate transport in gasoline particulate filters (GPFs). GPFs are emission control devices aimed at removing particulate out of the exhaust system of a gasoline direct injection engine. In this study, we consider a wall-flow uncoated GPF, which is made of a bundle of inlet and outlet channels separated by porous walls. The particulate-filled exhaust gas flows into the inlet channels, and passes through the porous walls before exiting out of the outlet channels. We model the flow inside the inlet and outlet channels using the incompressible Navier–Stokes equation coupled with the spatially averaged Navier–Stokes equation for the flow inside the porous walls. For the particulate transport, the coupled advection and spatially averaged advection–reaction equations are used, where the reaction term models the particulate accumulation. Using OpenFOAM, we numerically solve the flow and the transport equations and show that the concentration of deposited particles is nonuniformly distributed along the filter length, with an increase of concentration at the back end of the filter as Reynolds number increases. Images from X-ray computed tomography (XCT)-scanning experiments of the soot-loaded filter show that such a nonuniform distribution is consistent with the prediction obtained from the model. Finally, we show how the proposed model can be employed to optimize the filter design to improve filtration efficiency.