基于FGM的旋流预混燃烧室超大涡模拟

Very Large Eddy Simulation of Swirling Premixed Combustor Based on FGM

针对航空发动机燃烧室等复杂工程中的预混燃烧问题发展高精度、高效的数值预测方法,本研究发展了火焰面生成流型(FGM)详细化学反应建表方法结合超大涡模拟方法(VLES),对工程中的GE LM6000预混旋流燃烧室燃烧开展了高精度数值研究,并与实验结果进行了比较。计算结果表明,VLES-FGM方法可以较准确地预测出旋流预混燃烧室内的流场及温度场分布。为了进一步模拟航空发动机真实的燃烧工况,对原始单头部燃烧室使用周期性边界条件来类比全环燃烧室。计算结果表明,VLES-FGM方法计算得到的周期性燃烧室流场回流区相比较固壁边界燃烧室较小,并且固壁边界燃烧室温度场具有明显的颈部结构,燃烧室下游的高温区分布更为均匀。本文计算结果表明基于FGM燃烧模型的自适应湍流模拟方法VLES对于模拟复杂航空发动机相关的旋流预混燃烧具有很大的应用潜力。

In order to develop high fidelity and efficient numerical methods for premixed combustion simulations in complex engineering applications such as aero-engine combustor,a numerical approach is proposed based on the Flamelet Generated Manifolds(FGM),which is one of the detailed chemistry tabulation methods,coupled with the Very Large Eddy Simulation(VLES)method.It is then applied to study the swirling premixed flame in a simplified combustor,i.e.GE LM6000 and the simulation results are compared with the experimental data in detail.The results indicate that the present VLES-FGM method can accurately predict the velocity and temperature flow fields in the swirling premixed combustor.To further simulate the combustion process in real aero-engine working conditions,the periodic boundary condition is applied to imitate the boundary conditions in the annular combustor.The results show that the recirculation zone in the periodic combustor predicted by VLES-FGM is smaller than that in the wall confined combustor.Moreover,the temperature flow field in the wall confined combustor shows a significant neck flow structure and the high temperature zone downstream the combustor is more evenly distributed.The present study indicates that the adaptive turbulence modeling method,i.e.VLES,coupled with FGM combustion model has high potential to simulate the swirling premixed combustion in complex aero-engine applications.