单孔射流流化床内颗粒混合特性的数值模拟

发布时间：2018-06-09 04:09

本文选题：流化床 + 颗粒　；参考：《化工学报》2017年03期

【摘要】：在欧拉-拉格朗日坐标系下,采用离散单元法对单孔射流流化床内颗粒混合特性进行了数值模拟。引入混合指数对床内轴向及径向布置的颗粒混合质量进行定量分析,并研究了不同表观气速、不同弹性系数对颗粒混合特性的影响。模拟得到了颗粒轴向及径向混合序列图、气体和颗粒速度分布、整床颗粒混合指数分布、参量变化时整床颗粒混合指数分布。结果表明:流化床床层内颗粒混合速度受颗粒内循环能力和颗粒扩散能力的综合作用。单口射流喷动流化床颗粒轴向混合速度主要由颗粒内循环速度决定,颗粒径向混合速度主要由颗粒扩散能力决定。表观气速增大时,颗粒内循环速度增加,从而加快了颗粒轴向混合进程,但对颗粒径向混合影响微弱;弹性系数增大时,颗粒混合速度及混合质量均下降,并且弹性系数增大对颗粒径向混合进程影响小于颗粒轴向混合。
[Abstract]:In the Euler-Lagrangian coordinate system, the particle mixing characteristics in a fluidized bed with a single hole jet were numerically simulated by discrete element method. The mixing quality of particles arranged in axial and radial direction in the bed was quantitatively analyzed by introducing mixing index. The effects of different apparent gas velocity and different elastic coefficient on the mixing characteristics of particles were studied. The axial and radial mixing sequences of particles, the distribution of gas and particle velocity, the index distribution of particle mixing in whole bed and the exponential distribution of mixing index in whole bed are obtained by simulation. The results show that the particle mixing velocity in the fluidized bed is affected by both the circulating capacity and the diffusion capacity of the particles in the fluidized bed. The axial mixing velocity of single jet spouted fluidized bed is mainly determined by the particle circulation velocity, and the particle radial mixing velocity is mainly determined by the particle diffusion ability. With the increase of apparent gas velocity, the velocity of particle internal circulation increases, which speeds up the process of particle axial mixing, but has a weak effect on the radial mixing of particles, and when the elastic coefficient increases, both particle mixing velocity and mixing mass decrease. The effect of increasing elastic coefficient on the radial mixing process of particles is smaller than that of axial mixing.
【作者单位】：华北电力大学动力工程系;中国科学院工程热物理研究所;
【基金】：国家自然科学基金优秀青年基金项目(51522605) 国家国际科技合作专项项目(2014DFA60600) 中国科学院可再生能源高效利用创新交叉团队项目~~
【分类号】：TQ051.13

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