炉内两相流动和煤粉燃烧的双流体-轨道模型

NUMERICAL MODELING OF 3-D GAS-PARTICLE FLOWS AND COAL COMBUSTION IN A TANGENTIALLY-FIRED FURNACE USING A TWO-FLUID-TRAJECTORY MODEL

本文首次用双流体一轨道（连续介质－轨道ＣＴ）模型对大尺寸四角喷燃炉内气粒两相流动及煤粉燃烧进行了模拟。该模型基于欧拉气相方程组、欧拉颗粒连续方程和动量方程以及拉氏颗粒能量和质量变化的方程，对各子模型用ｋ－ε－ｋｐ两相湍流模型，ＥＢＵ－Ａｒｒｈｅｎｉｕｓ湍流燃烧模型，煤粉颗粒的水分蒸发，热解挥发和焦炭燃烧的扩散－动力模型，ＤＯ（离散坐标）辐射模型。采用了将坐标扭转一定角度的方法减小入口射流和网格斜交造成的伪扩散。编制了ＬＥＡＧＡＰ－ＦＵＲＮＡＣＥ－３程序，分别对冷态模型炉内两相流动和大尺寸炉内三维两相流动和煤粉燃烧进行了模拟，并与颗粒轨道（ＳＴ）模型的模拟结果进行了对照。采用ＰＤＰＡ对冷态模型炉内气粒两相流场进行了测量。冷态两相流动的模拟与实验结果的对比表明ＣＴ模型的模拟结果和实验符合较好，ＳＴ模型所得颗粒浓度分布和实验山入较大。热态模拟的结果给出了两相速度，气相温度，组分浓度和壁面热流分布。模拟结果定性合理。模拟结果显示在出口处由于气流旋转，有一局部高温区存在。

A two-fluid-trajectory (CT) model together with k-ε-kp two-phase turbulence model, EBU-Arrhenius model of volatile and CO combustion, DO radiation model, models of moisture evap- oration, devolatilization and char combustion, is used to simulate 3-D gas-particle flows and coal combustion in a tangentially-fired furnace. The cold two-phase flow predictions are compared with the PDPA measurements, and both cold-flow and hot-flow predictions using the CT model are compared with those using the stochastic trajectory (ST) model. The results show that the CT model is more reasonable than the ST model.