Luo, Y. ; Strassacker, C. ; Ferraro, F. ; Zentgraf, F. ; Dreizler, A. ; Maas, U. ; Hasse, C. (2022)
A manifold-based reduction method for side-wall quenching considering differential diffusion effects and its application to a laminar lean dimethyl ether flame.
In: International Journal of Heat and Fluid Flow, 97
doi: 10.1016/j.ijheatfluidflow.2022.109042
Article, Bibliographie

Abstract

In the present study, reduced kinetics considering both differential diffusion effects and strong heat losses, based on the Reaction–Diffusion Manifold (REDIM) method, formulated and constructed in generalized coordi-nates, is proposed. The approach fully coupled to a CFD solver is applied to the side-wall quenching (SWQ) of a laminar premixed dimethyl ether–air flame at an equivalence ratio of 0.83 where differential diffusion effects are non-negligible and a detailed transport model is required. To the best of the authors’ knowledge, this is the first study to take into account differential diffusion effects in manifold-based reduced kinetic models for complex scenarios such as the SWQ process, while previous studies with reduced models simply adopted a unity Lewis number assumption. Additionally, this is the first combined experimental-numerical study, including simulations with manifold-based reduced models, for SWQ with differential diffusion. To consider differential diffusion effects, strong heat losses, and their interactions, two different reduced kinetic models based on a three-dimensional and a two-dimensional REDIM, respectively, are formulated and assessed. The performance of the reduced kinetics is evaluated by comparison with detailed kinetics and experimental data for global quenching characteristics, local thermo-chemical states and stretch distribution in the near-wall region. It is found that major features observed in the detailed kinetic computation and experiment are well reproduced by both reduced kinetic simulations. The capability of the reduced kinetics to describe the multiple physical phenomena present in the SWQ configuration, such as differential diffusion, heat losses, flame quenching and stretch effects is demonstrated. The two different reduced kinetic models are compared to each other and the advantages and disadvantages of each method are discussed, which can be useful when choosing the modeling approach for more complex configurations.

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