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A transient, 3-dimensional, continuum CFD model of soot loading and regeneration has been developed for a single channel unit in a diesel particulate filter. The detailed model is used to predict the soot loading, velocity, temperature, and species distributions in both the air channels and porous walls of the filter. The simulation is performed in two phases: loading and regeneration. In the loading phase, soot profiles are estimated for a clean filter using a steady-state simulation. In the second phase, transient regeneration is modeled using a single-step, irreversible heterogeneous mechanism is used to predict the formation of carbon monoxide and carbon dioxide products during the regeneration process, incorporating a fractionization scheme. Reaction rates are predicted via an Arrhenius rate law, but may be tempered due to diffusion-limiting conditions in the porous reaction zone. Simulations are performed with a commercial CFD package and user-defined functions.

In this case study, the thermoforming of an automotive instrument panel is considered. The effect of different oven settings on the final material distribution is studied using structural FEA simulation. The variable thickness distribution of the thermoformed part is mapped onto a structural model using a new simple mapping algorithm, and a structural FEA simulation is carried out to examine the final warpage of the instrument panel. The simulation predicts that the minimum thickness of the formed part can be increased by 10% by optimizing the oven settings. Although the optimized process uses oven settings that are less uniform than the baseline settings, the model indicates that warpage experienced by the optimized part will be less than that of the baseline case.