Soot formation and radiation are important aspects for combustion problems. In this work, numerical simulations of ethylene coflow laminar flames are used to evaluate soot formation and radiation processes under different modeling approximations. Priority was given for models that were capable of producing detailed information with reduced computational requirements. So, the objective of this work is to show and quantify the importance of heat loss by gas and soot radiation and to quantitatively show the impact of different transport models (a detailed and a simplified) in soot predictions. For soot modeling, a semiempirical two-equation model is chosen for predicting soot mass fraction and number density. The model describes particle nucleation, surface growth and oxidation. For flame radiation, the radiant heat losses (gas and soot) are modeled by using the gray-gas approximation with optically thin approximation. For the chemical kinetics, a detailed approach is employed. It is found that gas and soot components of the radiative heat loss are comparable, with the gas radiation being larger (65%). To capture 99.9% of the total heat loss, the numerical domain has to be extended to 2.4 times the flame length based on the stoichiometric mixture fraction. Radiation modeling has a large impact on soot predictions. An error of 19% in the peak soot volume fraction is found when radiation is neglected. Errors due to simplified transport properties are also around 21%.

烟灰的形成和辐射是燃烧问题的重要方面。在这项工作中，乙烯同流层流火焰的数值模拟用于评估在不同模型近似下的烟灰形成和辐射过程。优先考虑能够生成详细信息且计算需求减少的模型。因此，这项工作的目的是显示和量化气体和烟尘辐射造成的热损失的重要性，并定量显示烟尘预测中不同传输模型（详细和简化）的影响。对于烟灰建模，选择半经验两方程模型来预测烟灰质量分数和数密度。该模型描述了颗粒成核，表面生长和氧化。对于火焰辐射，辐射热损失（气体和烟灰）是通过使用灰气体近似和光学薄近似来模拟的。对于化学动力学，采用了详细的方法。发现辐射热损失的气体和烟尘成分相当，气体辐射较大（65％）。为了捕获99.9％的总热损失，基于化学计量的混合物分数，数值域必须扩展到火焰长度的2.4倍。辐射建模对烟尘预测有很大影响。当忽略辐射时，发现烟灰峰值体积分数的误差为19％。由于简化的传输特性而导致的错误也约为21％。发现辐射热损失的气体和烟尘成分相当，气体辐射较大（65％）。为了捕获99.9％的总热损失，基于化学计量的混合物分数，数值域必须扩展到火焰长度的2.4倍。辐射建模对烟尘预测有很大影响。当忽略辐射时，发现烟灰峰值体积分数的误差为19％。由于简化的传输特性而导致的错误也约为21％。发现辐射热损失的气体和烟尘成分相当，气体辐射较大（65％）。为了捕获99.9％的总热损失，基于化学计量的混合物分数，数值域必须扩展到火焰长度的2.4倍。辐射建模对烟尘预测有很大影响。当忽略辐射时，发现烟灰峰值体积分数的误差为19％。由于简化的传输特性而导致的错误也约为21％。当忽略辐射时，发现烟灰峰值体积分数的误差为19％。由于简化的传输特性而导致的错误也约为21％。当忽略辐射时，发现烟灰峰值体积分数的误差为19％。由于简化的传输特性而导致的错误也约为21％。