大涡模拟模型燃烧室燃烧性能计算

对带双级扩压器的模型燃烧室气液两相瞬态喷雾燃烧过程,在三维贴体坐标系下采用欧拉-拉格朗日两相大涡模拟方法进行数值研究,同时采用多维经验分析法预估燃烧性能.采用k方程亚网格尺度模型模拟亚网格湍流黏性;亚网格EBU（eddy-break-up）燃烧模型预估化学反应速率;多维经验分析法计算燃烧性能;并在非交错网格体系下气相采用SIMPLE（semi-implicit method for pressure-linked equations）算法对控制方程进行求解,液相采用随机离散模型,两相之间的耦合采用PSIC（particle-source-in-cell）算法.通过大涡模拟瞬态及时均计算结果表明：与粒子图像测速仪（PIV）测量的瞬态速度场、出口温度分布试验数据吻合,表明在三维贴体坐标系下采用欧拉-拉格朗日两相大涡模拟方法,数值模拟模型燃烧室两相喷雾燃烧流场,所采用的亚网格模型可以用于燃烧室气液两相喷雾燃烧流场的大涡模拟;燃烧性能计算结果与试验测量结果基本一致,说明所采用多维经验分析法可以用来数值模拟航空发动机燃烧室燃烧性能的计算,特别是污染物的预估,为设计低污染高性能航空发动机燃烧室提供有用的设计依据.

Large-eddy simulation of two-phase reacting flows and combustion performance in model combustor

Instantaneous gas-liquid two-phase turbulent combustion flows in model combustor were computed by using an Eulerian-Lagrangian two phase large-eddy simulation (LES) approach in three-dimensional arbitrary curvilinear coordinates,and combustion performance was estimated by an empirical-analytical design methodology.The k-equation subgrid scale model was used to calculate the subgrid eddy viscosity,and the EBU (eddy-break-up) subgrid scale combustion model was applied to predict the chemical reaction rate.The gas phase governing equations were solved by SIMPLE (semi-implicit method for pressure-linked equations) algorithm in non-staggered grid system,and a stochastic separated flow formulation was employed to track the droplet trajectory velocities,sizes and temperature history by Lagrangian equations of motion and thermal balance.Numerical simulation results were in reasonable agreement with the instantaneous velocity by particle image velocimetry (PIV) system and temperature measurements at the exit plane.It shows that in an arbitrary curvilinear coordinates,the Eulerian-Lagrangian two phase LES formulation can be used to investigate turbulent two-phase reacting flows and combustion process in model combustor,and combustion performance results are in reasonable agreement with the measurement results.It shows that the empirical-analytical design methodology can be applied to predict the combustion performance in gas turbine combustors,especially for pollution emissions,and it provides a useful tool for designing advanced gas turbine combustor of low emissions of pollutant and high performance.