Large Eddy Simulations (LES) of a swirl-stabilized natural gas-air flame in a laboratory gas turbine combustor is performed using six different LES combustion models to provide a head-to-head comparative study. More specifically, six finite rate chemistry models, including the thickened flame model, the partially stirred reactor model, the approximate deconvolution model and the stochastic fields model have been studied. The LES predictions are compared against experimental data including velocity, temperature and major species concentrations measured using Particle Image Velocimetry (PIV), OH Planar Laser-Induced Fluorescence (OH-PLIF), OH chemiluminescence imaging and one-dimensional laser Raman scattering. Based on previous results a skeletal methane-air reaction mechanism based on the well-known Smooke and Giovangigli mechanism was used in this work. Two computational grids of about 7 and 56 million cells, respectively, are used to quantify the influence of grid resolution. The overall flow and flame structures appear similar for all LES combustion models studied and agree well with experimental still and video images. Takeno flame index and chemical explosives mode analysis suggest that the flame is premixed and resides within the thin reaction zone. The LES results show good agreement with the experimental data for the axial velocity, temperature and major species, but differences due to the choice of LES combustion model are observed and discussed. Furthermore, the intrinsic flame structure and the flame dynamics are similarly predicted by all LES combustion models examined. Within this range of models, there is no strong case for deciding which model performs the best.

中文翻译：

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有限速率化学大涡模拟燃烧模型的评估

使用六种不同的 LES 燃烧模型对实验室燃气轮机燃烧器中的涡流稳定天然气-空气火焰进行大涡模拟 (LES)，以提供头对头的比较研究。更具体地说，研究了六种有限速率化学模型，包括增稠火焰模型、部分搅拌反应器模型、近似解卷积模型和随机场模型。将 LES 预测与实验数据进行比较，包括使用粒子图像测速法 (PIV)、OH 平面激光诱导荧光 (OH-PLIF)、OH 化学发光成像和一维激光拉曼散射测量的速度、温度和主要物质浓度。基于先前的结果，在这项工作中使用了基于众所周知的 Smooke 和 Giovangigli 机制的骨架甲烷-空气反应机制。分别使用大约 7 和 5600 万个单元的两个计算网格来量化网格分辨率的影响。对于所研究的所有 LES 燃烧模型，整体流动和火焰结构看起来相似，并且与实验静止图像和视频图像非常吻合。武野火焰指数和化学炸药模式分析表明，火焰是预先混合的，并位于薄反应区内。LES 结果与轴向速度、温度和主要物种的实验数据非常吻合，但观察和讨论了由于 LES 燃烧模型的选择而产生的差异。此外，所有 LES 燃烧模型都类似地预测了固有的火焰结构和火焰动力学。在这个模型范围内，没有充分的理由来决定哪个模型表现最好。