多喷嘴对置式煤气化炉内气固两相流动及壁面沉积  

Gas-solid two-phase flows and particle deposition on internal wall in coal gasifier with multi opposed injectors

作　　者：郝英立[1] 许忠林[1] 刘升[1] 

机构地区：[1]东南大学能源与环境学院,南京210096

出　　处：《东南大学学报（自然科学版）》2008年第3期461-467,共7页Journal of Southeast University：Natural Science Edition

基　　金：国家重点基础研究发展计划(973计划)资助项目(2004CB217703)

摘　　要：对我国具有自主知识产权的多喷嘴对置式煤气化炉内的气固两相流进行了数值模拟分析.在合理简化和假设基础上建立了基于Eulerian-Lagrangian模拟方法的炉内气固两相流动模型,采用Realizablek-ε模型描述炉内复杂气相湍流运动,应用颗粒轨道模型随机追踪煤粉颗粒在湍流气流中的运动.通过数值计算获得了炉内气固两相的速度矢量、颗粒分布、颗粒运动轨迹,以及颗粒碰撞并沉积于壁面的通量分布.揭示了该型气流床煤气化炉内气固两相流动特征,并分析了入口速度和炉体上部高度对气固两相流动和颗粒在壁面沉积的影响规律.结果表明:对撞流显著增强炉内气固流动湍动,强化气固相互作用,并使煤粉颗粒在炉内有效分散,有利于化学反应高效进行;在喷嘴入口及顶部的壁面处颗粒沉积率较大.The numerical simulation of gas-solid two-phase flows in a coal gasifier with multi opposed injectors of domestic intellectual property was carded out. A model based on Eulerian-Lagrangian approach for the gas-solid two-phase flows in the gasifier was proposed after reasonable simplifications and hypotheses. The realizable k-ε model was used to simulate the complex turbulent gas flow while the coal particle trajectories were calculated by Lagrangian method. The velocity vec- tors of gas and solid phases, the distribution of volume fraction of particle, and the trajectories of particle in the gasifier were obtained. The distribution of deposition flux of particle on the internal wall was also obtained. The characteristics of gas-solid two-phase flows in the entrained-flow coal gasifier were revealed. The effects of the inlet velocity and the height of section above the injectors on the gas-solid flows and the particle deposition on the internal wall were numerically analyzed. The results indicate that the opposed impinging flow remarkably affects the turbulence of gas-solid flows and enhances the interactions between gas and solid phases causing the particles to disperse which benefits the chemical reactions. It is also shown that the deposition flux is bigger in the walls nearby the nozzles and at the top.

关 键 词：湍流 气固两相流 Eulerian-Lagrangian方法 Realizable k-ε模型 颗粒沉积 

分 类 号：O359[理学—流体力学]