A new approach for calculating flow domains with embedded monoliths is presented, focusing on a system suitable for an automotive converter. Using appropriate boundary conditions, the monolith itself can be excluded from the CFD computational domain, leaving two mapped computational domains upstream and downstream of the monolith. The resulting method enables more detailed results of the downstream flow profile than afforded by the commonly used porous body approach for simulating a monolith, but without the complexities of a full 3D calculation of the entire domain, including the monolith. The present approach was validated with experimental flow data from the literature collected with a prismatic (planar) monolith with approximately 4500 channels. Sensitivity studies were performed to check the influence of the downstream turbulence model, inlet turbulence boundary conditions, and spatial discretization schemes. RANS turbulence models (k-ω SST and k-ε) generally predict the experimentally measured flow profile downstream of the monolith although the transition to turbulence cannot be reproduced correctly. Currently, LES is the best approach for adequately describing the characteristics of flow downstream of monoliths.

提出了一种用于计算带有嵌入式整体结构的流域的新方法，重点是适用于汽车转换器的系统。使用适当的边界条件，可以将整体结构本身从CFD计算域中排除，从而在整体结构的上游和下游留下两个映射的计算域。与用于模拟整体结构的常用多孔体方法所提供的方法相比，所产生的方法能够获得更详细的下游流动剖面结果，但没有包括整体结构在内的整个域的完整3D计算的复杂性。本方法已通过文献收集的实验流量数据进行了验证，该文献使用的是具有约4500个通道的棱柱形（平面）整料。进行了敏感性研究，以检查下游湍流模型的影响，入口湍流边界条件和空间离散方案。RANS湍流模型（k-ωSST和k-ε）通常可预测在整料下游的实验测得的流量分布，尽管无法正确再现向湍流的过渡。当前，LES是充分描述整料下游流动特性的最佳方法。