The numerical investigation of quenching distances in laminar flows is mainly concerned with two setups: head-on quenching (HOQ) and side-wall quenching (SWQ). While most of the numerical work has been conducted for HOQ with good agreement between simulation and experiment, far less analysis has been done for SWQ. Most of the SWQ simulations used simplified diffusion models or reduced chemistry and achieved reasonable agreement with experiments. However, it has been found that quenching distances for the SWQ setup differ from experimental results if detailed diffusion models and chemical reaction mechanisms are employed. Side-wall quenching is investigated numerically in this work with steady-state 2D and 3D simulations of an experimental flame setup. The simulations fully resolve the flame and employ detailed reaction mechanisms as well as molecular diffusion models. The goal is to provide data for the sensitivity of numerical quenching distances to different parameters. Quenching distances are determined based on different markers: chemiluminescent species, temperature and OH iso-surface. The quenching distances and heat fluxes at the cold wall from simulations and measurements agree well qualitatively. However, quenching distances from the simulations are lower than those from the experiments by a constant factor, which is the same for both methane and propane flames and also for a wide range of equivalence ratios and different markers. A systematic study of different influencing factors is performed: Changing the reaction mechanism in the simulation has little impact on the quenching distance, which has been tested with over 20 different reaction mechanisms. Detailed diffusion models like the mixture-averaged diffusion model and multi-component diffusion model with and without Soret effect yield the same quenching distances. By assuming a unity Lewis number, however, quenching distances increase significantly and have better agreement with measurements. This was validated by two different numerical codes (OpenFOAM and FASTEST) and also by 1D head-on quenching simulations (HOQ). Superimposing a fluctuation on the inlet velocity in the simulation also increases the quenching distance on average compared to the reference steady-state case. The inlet velocity profile, temperature boundary condition of the rod and radiation have a negligible effect. Finally, three dimensional simulations are necessary in order to obtain the correct velocity field in the SWQ computations. This however has only a negligible effect on quenching distances.

中文翻译：

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使用详细扩散和化学方法对侧壁淬火的淬火距离进行数值研究

层流中淬火距离的数值研究主要涉及两种设置：正面淬火 (HOQ) 和侧壁淬火 (SWQ)。虽然大多数数值工作是针对 HOQ 进行的，模拟和实验之间具有良好的一致性，但对 SWQ 进行的分析却少得多。大多数 SWQ 模拟使用简化的扩散模型或减少的化学反应，并与实验取得了合理的一致性。然而，已经发现如果采用详细的扩散模型和化学反应机制，SWQ 设置的淬火距离与实验结果不同。在这项工作中，通过实验火焰设置的稳态 2D 和 3D 模拟，对侧壁淬火进行了数值研究。模拟完全解析火焰并采用详细的反应机制以及分子扩散模型。目标是为数值淬火距离对不同参数的敏感性提供数据。淬灭距离是根据不同的标记确定的：化学发光物质、温度和 OH 等值面。来自模拟和测量的冷壁处的淬火距离和热通量在质量上非常吻合。然而，模拟的淬火距离低于实验的淬火距离，这是一个常数因子，这对于甲烷和丙烷火焰以及广泛的当量比和不同标记都是相同的。对不同影响因素进行了系统研究：在模拟中改变反应机制对淬灭距离影响很小，已经用 20 多种不同的反应机制进行了测试。详细的扩散模型，如混合平均扩散模型和具有和不具有 Soret 效应的多组分扩散模型，产生相同的淬灭距离。然而，通过假设统一的刘易斯数，淬灭距离显着增加并且与测量值更加一致。这通过两种不同的数字代码（OpenFOAM 和 FASTEST）以及一维正面淬火模拟 (HOQ) 进行了验证。与参考稳态情况相比，在模拟中叠加入口速度的波动也增加了平均淬火距离。入口速度剖面，棒的温度边界条件和辐射的影响可以忽略不计。最后，为了在 SWQ 计算中获得正确的速度场，需要进行三维模拟。然而，这对淬火距离的影响可以忽略不计。