带有Kenics静态混合器的水平液固循环流化床流动特性的数值研究-化工过程机械专业论文.docxVIP

河 河北工业大学硕士学位论文 I I PAGE PAGE IV PAGE PAGE III 摘 要 在水平管液固循环流化床中，因受到重力作用，颗粒在流化床换热器中的分布很 不均匀，具体表现在颗粒在流动一段距离后，会出现下沉，从而影响水平液固循环流 化床性能。 为了改善这种情况，本文利用 STAR-CCM+软件建立 Eulerian-Lagrangian 模型， 对加入 Kenics 静态混合器后水平管内低浓度液固两相流动特性进行了数值模拟，考察 了雷诺数、Kenics 静态混合器扭率、颗粒体积分数对水平管中颗粒分布的影响，同时 考察了雷诺数、Kenics 静态混合器扭率、颗粒体积分数对压降的影响。 研究结果表明：液体流速、Kenics 静态混合器扭率、颗粒体积分数对颗粒分布都 有重要影响，随着扭率的增大，颗粒分布越均匀；扭率一定时，颗粒体积分数为 4% 时的颗粒分布均匀情况最好，管路压降随着流速、颗粒初始加入量及液相粘度的增大 而增大，随 Kenics 静态混合器扭率的减小而增大，最后通过线性回归得到 Kenics 静 态混合器阻力系数关联式。数值模拟结果与实验数据吻合较好，为水平液固循环流化 床中 Kenics 静态混合器的设计和选型提供一定的依据。 关键词：液固循环流化床 Kenics 静态混合器 颗粒分布 压强 数值模拟 水平管 河 河北工业大学硕士学位论文 ABSTRACT The distribution of particles in the horizontal liquid-solid circulating fluidized bed is not uniform, for that the particles begin to sink after a distance in the tube because of its gravity, thus it will seriously affects the performance of horizontal liquid-solid circulating fluidized bed. In order to improve this situation, flow characteristics due to Kenics static mixer of liquid-solid two-phase flow for low concentration in horizontal pipe is numerically studied using the Eulerian-Lagrangian model in software STAR-CCM+. The effects of Reynolds number, Kenics static mixer twist ratio and solid volume fraction on the particle distribution of Kenics static mixer were discussed. Simultaneously ,the effects of these factors on pressure drop were also studied. The resrach suggsts that: the liquid velocity, Kenics static mixers twist rate, volume fraction of particle have a significant impact on the particle distribution.With the increasing of twist rate, the distribution of particle become more uniform.Besides, under the condision of the identical twist rate of Kenics static mixer, the uniform distribution of particles indicates preferably .with the particle volume fraction of 4%. Pressure drop of the pipeline decreases as the liquid velocity, particle volume fraction and liquid viscosity enlarges,.while with the decrease of the Kenics static mixer twist rate the ressure