流化床炉内颗粒混合的离散单元法数值模拟  

Numerical Simulation of Particle Mixing in Circulating Fluidized Bed With Discrete Element Method

作　　者：李斌[1] 纪律[2] 

机构地区：[1]华北电力大学动力工程系,河北省保定市071003 [2]中国科学院工程热物理研究所,北京市海淀区100190

出　　处：《中国电机工程学报》2012年第20期42-48,137,共7页Proceedings of the CSEE

摘　　要：为了更好地研究流化床内复杂的运动和颗粒间的混合情况,为流化床的设计及优化提供参考,采用欧拉–拉格朗日坐标系下的离散单元法软球模型在二维空间对单孔射流流化床内气固两相流动进行了数值模拟。其中颗粒相采用离散单元法,气相的计算采用SIMPLER算法,气固两相间遵循牛顿第三定律建立耦合模型,并用FORTRAN语言编程计算来实现。在假设不考虑传热、燃烧及颗粒转动的条件下,模拟得到了流化床内上下两层颗粒的运动和混合情况、气固两项的速度分布以及颗粒的浓度分布。模拟结果表明:由于受到空气射流的影响,流化床内存在强烈的颗粒返混和内循环现象。固体颗粒在横向和纵向都存在一定的浓度梯度,在空间中的碰撞次数分布也有不同,颗粒浓度高的地方颗粒碰撞和混合会更剧烈。In order to study the complex movement and the mixing of particle in fluidized bed better,the gas-solid two-phase flow in the single spouted fluidized bed was stmulated in two space dimensions by the soft-sphere model of discrete element method in Euler-Lagrange coordinate system.The particle phase was simulated by discrete element method,and the gas phase by the algorithm of SIMPLER.The gas-solid phase built coupling model by Newton third law and the calculation was carried out by using FORTRAN program.Heat transfer,combustion and particles’ rotation were neglected.The simulation obtained the movement and mixing of particles in the top and bottom layers,velocity of gas-solid in different heights and particle concentration distribution.The results show that the back-mixing of intensive particles and internal recycle phenomenon are existed in fluidized bed under the influence of the air jet.There is a certain particle concentration gradient in the horizontal and vertical direction.The number of particle collisions is also different.The higher of the particle concentration is in the place the intenser of the particle collisions and mixing are.

关 键 词：流化床 气固两相流 离散单元法 数值模拟 颗粒混合 

分 类 号：TK224[动力工程及工程热物理—动力机械及工程]