fluent 教程 粉煤燃烧

1、粉煤燃烧 模拟连续相与稀疏相煤颗粒燃烧 煤颗粒穿越气体，经过挥发份挥发，碳核燃烧，产生气相燃烧的源项 采用有限速率化学动力学或混合分数PDF模拟 下面介绍混合分数PDF模拟 1，用prePDF建表 2，给定PDF化学模拟 3，指定煤颗粒为稀疏第二相 4，求解包括系数颗粒反应在内的气固两相流问题长10米，直径为1米的管道型燃烧室，二维，算一半0.5米中心0.125米以内，速度50米/秒其它0.375米为15米/秒，温度1500K煤粉在告诉气流中加入，质量流量为：0.1kg/s (总共为0.2kg/s)腔体壁面温度1200K，雷诺数：100000，为湍流混合分数PDF模型一，用PDF系统研究绝热系

2、统Set-case击活二次流（挥发份）（燃料流为碳核）Empirically defined Streams绝热化学平衡组分的选择：Setup-species13组分13 species: C, C(s), CH4, CO, CO2, H, H2, H2O, N, N2, O, O2, and OH. 给定煤燃料组分Setup-species-composition燃料：C5H12质量分数1氧化剂：O2，摩尔分数0.21N2， 摩尔分数0.79ElementMassWt %MolesMole FractionC(89.3 - 69.6)0.655.40.24H5.00.16160.70O3.4

3、0.110.70.03N2.30.080.60.03Total30.422.7密度Setup-species-densityH2O(L):1000C(s): 1700进口条件Setup-operating conditions燃料进口：303K氧化剂进口650K 定义PDF求解条件Setup-solution parameters保存输入参数：file-write-input求解：calculate-PDF table保存PDF文件：file-write-PDF检查PDF计算结果Graphics-Property Curves温度混合分数之间关系：f=0.1；T2270K组分在混合分数空间分布

4、非绝热的设置和PDF计算Operating conditionSetup-solution ParametersFLUENT 计算读入网格检查网格显示网格非耦合求解器标准双方程模型PDF模型（非预混模型）离散相与气相耦合：define-models-discrete phaseDefine-InjectionsGroup injectionNumber of particles streams: 10Particle type: dropletMaterial: n-pentane-liquidDiameter distribution: linearEvaporating species:

5、C5H12Stochastic model: number of tries: 10First PointLast PointX-Position (m)0.0010.001Y-Position (m)0.0010.001X-Velocity (m/s)100100Y-Velocity (m/s)057.7Diameter (m)1.0E-41.0E-4Temperature (K)303303Flow Rate (kg/s)2.0E-42.0E-4These initial conditions define the spray of liquid fuel droplets with a

6、uniform diameter of 100 microns. The filled spray cone of 30 degree half-angle is defined by the range of Y-Velocity from 0 to 57.7 m/s. The total mass flow rate is 10 2.0E-4 = 0.002 kg/s. This corresponds to the mass flow of liquid fuel in the half of the symmetric duct considered here. Material: (

7、continuous phase)Cp: mixing-lawThermal conductivity: 0.025Viscosity :2.0e-5Materials: Discrete PhaseMaterials type: droplet-particleN-pentane-liquidDensity620 kg/m3Cp2300 J/kg-KThermal Conductivity0.136 W/m-KLatent Heat3.63E5 J/kgVaporization Temperature303 KBoiling Point306 KVolatile Component Frac

8、tion (%)100Binary Diffusivity6.1E-6 m2/sSaturation Vapor Pressure8.2E4 PaHeat of Pyrolysis0 J/kg边界条件：Set solutionP1: 松弛因子设为1初始化流场检查求解结果，显示，输出显示颗粒轨道：display-Particle Tracks显示组分分布：display-contours 包括氧气，二氧化碳，水，一氧化碳等计算通过计算区域边界的通量：Report-Fluxes: mass flow rate, total heat transfer rate, Radiation heat transfer rate et al.计算气相和离散相之间的换热Report-Volume Integrals小节 煤燃烧的模拟过程包括挥发份挥发和碳核的燃烧，以及气相的燃烧过程。本小节是用PDF混合分数化学平衡模型模拟气相燃烧。燃料的分解组分由prePDF给定，燃料的燃烧根据平衡系统