燃烧室两相流场亚网格燃烧模型的研究

SUB-GRID SCALE COMBUSTION MODELS FOR TWO-PHASE COMBUSTION FLOW IN AN ANNULAR COMBUSTOR

在三维任意曲线坐标系下采用不同的亚网格燃烧模型对环形燃烧室火焰筒气液两相湍流瞬态反应流进行大涡模拟．计算中所采用的数学度模型有：k方程亚网格尺度模型估算亚网格湍流黏性；热通量辐射模型估算辐射换热,分别采用亚网格EBU燃烧模型(E-A model)、亚网格二阶矩输运方程模型(SOM)和亚网格二阶矩代数模型(SOM-A)估算化学反应速率．并在非交错网格系统下气相采用SIMPLE算法和混合差分格式求解,液相采用Lagrange处理,并用PSIC算法对其进行求解．通过实验结果和计算结果的比较,表明在三维任意曲线坐标系下对燃烧室火焰筒两相湍流油雾燃烧流场进行大涡模拟,3种不同的亚网格燃烧模型都能真实反映两相湍流化学反应流流动及实际燃烧过程,而采用亚网格二阶矩输运方程模型稍优于其他两种亚网格燃烧模型．

An Eulerian-Lagrangian two phase large-eddy simulation （LES） is described for calculating the instantaneous gas-liquid two-phase turbulent reacting flow in an annular combustor by using different sub-grid scale combustion models. The k-equation sub-grid scale model is used to simulate the sub-grid eddy viscosity. The six-heat flux model is applied to predictions of the radiant heat transfer. The EBU combustion sub-grid scale model（E-A model）, the turbulent combustion second-order moment algebraic model（SOM-A Model） and the second-order moment transport model （SOM model） are, respectively, employed to determine the chemical reaction rate. Three-dimensional body fitted grid is generated by an elliptic grid generation procedure. The gas phase is solved with SIMPLE algorithm and hybrid scheme in the non-staggered grid system. The liquid phase equations are solved in a Lagrangian frame of reference by PSIC algorithm. From simulation results, the exchange of mass, momentum and energy between gas and fuel droplet can be obtained. Experimental and predicted results are shown to be in qualitative agreement, and the comparison shows that the large-eddy simulation method in an arbitrary curvilinear coordinates may be used to investigate two-phase reacting flows and the combustion process by using different sub-grid scale combustion models. SOM model is better than E-A Model and SOM-A Model in the simulations.