Optimized Reduced Chemistry and Molecular Transport for Large Eddy Simulation of Partially Premixed Combustion in a Gas Turbine
Optimized Reduced Chemistry and Molecular Transport for Large Eddy Simulation of Partially Premixed Combustion in a Gas Turbine
复制标题
DOI：
10.1080/00102202.2015.1074574
复制
发表时间：
2016-01-01
影响因子：
1.9
通讯作者：
Eriksson, L. -E.
中科院分区：
文献类型：
--
作者：
Abou-Taouk, A.;Farcy, B.;Eriksson, L. -E.
讨论了一种自动确定化学物质质量分数和能量的闭合预算方程参数的方法，以便模拟大涡模拟（LES）中所需的空间过滤火焰。该方法通过同时优化（减少物种数量）阿累尼乌斯反应速率和对混合物平均分子扩散系数的校正，解释了 LES 过滤对化学和传输的影响。目标是对于给定的过滤器尺寸，匹配用详细的化学溶液模拟的空间过滤的规范一维火焰。这种方法是为分辨率很好的 LES 设计的，其中大部分未解析的波动是由于空间过滤导致的火焰增厚造成的，因此具有弱水平的亚网格尺度火焰起皱。解决了甲烷-空气部分预混合燃烧问题。开发了涉及七种物质的四步还原反应机制以及质量和热分子传输特性。优化在大气压力和 3 bar 下进行，新鲜气体温度范围为 [300-650 K] 和当量比 [0.4-1.2]。与平面传播前沿的过滤详细化学溶液的比较表明，可以充分预测层流火焰速度、绝热火焰温度、反应区中的物质分布以及流动化学成分和平衡温度。然后，新的子网格尺度建模方法被应用于工业燃气轮机燃烧器的三维 LES。在流动和火焰动力学、轴向速度、平均温度和一些主要物质浓度方面，LES 预测的数量与实验数据之间存在良好的一致性。与之前对同一燃烧器的模拟相比，结果也有所改善。
A methodology is discussed to automatically determine the parameters of closed budget equations for chemical species mass fractions and energy, in order to simulate spatially filtered flames as required in large eddy simulation (LES). The method accounts for the effects of LES filtering on chemistry and transport by simultaneously optimizing, for a reduced number of species, the Arrhenius reaction rates and a correction to mixture-averaged molecular diffusion coefficients. The objective is to match, for a given filter size, spatially filtered canonical one-dimensional flames simulated with detailed chemistry solutions. This approach is designed for quite well-resolved LES, in which most of the unresolved fluctuations result from flame thickening due to spatial filtering, thus featuring weak levels of sub-grid scale flame wrinkling. Methane-air partially premixed combustion is addressed. A four-step reduced reaction mechanism involving seven species is developed along with mass and heat molecular transport properties. The optimization is performed at atmospheric pressure and at 3 bar, for ranges of fresh gas temperatures [300-650 K] and equivalence ratios [0.4-1.2]. Comparisons with the filtered detailed chemistry solution of a planar propagating front show that the laminar flame speed, the adiabatic flame temperature, the species profiles in the reaction zone, and the flow chemical composition and temperature at equilibrium are adequately predicted. The new sub-grid scale modeling approach is then applied to three-dimensional LES of an industrial gas turbine burner. Good agreement is found between the quantities predicted with LES and experimental data, in terms of flow and flame dynamics, axial velocities, averaged temperatures, and some major species concentrations. Results are also improved compared to previous simulations of the same burner.