A method for identifying radial concentration maldistribution in synthetic catalyst activity test (SCAT) benches, is presented, where spatially resolved concentration measurements are not available. The developed methodology was successfully tested for an injection-based SCAT. To resolve the radial concentration maldistribution a static mixer was designed, 3D-printed and inserted upstream the test sample. The methodology could also prove the effectiveness of the mixer, which did not only resolve the concentration maldistribution but also avoided causing reaction disturbances. The resulting increased axial dispersion from the turbulence created by the static mixer was evaluated using a 3D CFD model in Ansys Fluent 19. The axial dispersion of the injection-based SCAT bench was compared to a premixed SCAT bench through classical Aris-Taylor calculations. The results from the axial dispersion calculations show that the injection-based design with the use of a static mixer is far superior to the premixed design – both with regards to pulse broadening but also time delay. This is highly desirable for modelling studies towards zero emission exhaust aftertreatment.

提出了一种在合成催化剂活性测试（SCAT）工作台中识别径向浓度分布不均的方法，该方法无法获得空间分辨的浓度测量值。所开发的方法已成功测试了基于注射的SCAT。为了解决径向浓度分布不均的问题，设计了静态混合器，进行3D打印并插入到测试样品的上游。该方法还可以证明混合器的有效性，该混合器不仅解决了浓度分布不均，而且避免了引起反应干扰。在Ansys Fluent 19中使用3D CFD模型评估了由静态混合器产生的湍流导致的轴向扩散增加。通过经典的Aris-Taylor计算，将基于注射的SCAT工作台的轴向扩散与预混合的SCAT工作台进行了比较。轴向色散计算的结果表明，使用静态混合器的基于注射的设计要远远优于预混合的设计-无论是在脉冲展宽方面还是在时间延迟方面。这对于对零排放废气后处理进行建模研究是非常理想的。