基于DEM的流化床气固两相流瞬态数值模拟与验证

发布时间：2018-08-12 16:58

【摘要】：为了突破均相流模型不能全面考虑颗粒碰撞过程中受力的瓶颈,采用基于欧拉-拉格朗日方法的DEM离散元模拟方法,对准三维鼓泡流化床起始阶段的气固两相运动进行了瞬态数值模拟.结合流化床起始过程的高速摄影试验结果,从床层高度、空泡大小的变化以及颗粒相运动特性等角度对比分析了试验结果和数值计算结果.发现在流化床鼓泡的初始阶段,DEM模型的预测结果和试验结果吻合较好,床层高度和空泡形态基本一致;在流化床内由于高速气流和颗粒相互作用产生的空泡临近破碎的阶段,DEM预测的空泡直径和床层高度均小于试验测量结果.但是从整体流体动形态以及颗粒运动轨迹等角度,DEM模型能够较为准确地对稠密两相流进行求解,同时也能较好地描述气固流化床内的动力学特性,研究结果对工程实际具有重要的指导意义.
[Abstract]:In order to break through the bottleneck of the homogeneous phase flow model, the DEM discrete element simulation method based on Euler-Lagrangian method is adopted. The transient numerical simulation of gas-solid two-phase motion in the initial stage of three-dimensional bubbling fluidized bed was carried out. The experimental results and numerical results are compared and analyzed from the point of view of bed height, cavitation size and particle phase motion characteristics, combined with the results of high-speed photography in the initial process of fluidized bed. It is found that the predicted results of Dem model in the initial stage of fluidized bed bubbling are in good agreement with the experimental results, and the bed height is basically consistent with the cavitation shape. The bubble diameter and bed height predicted by Dem in fluidized bed are smaller than the experimental results. However, Dem model can solve the dense two-phase flow accurately from the point of view of the whole fluid dynamic morphology and particle trajectory, and can also describe the dynamic characteristics of gas-solid fluidized bed. The results of the study are of great significance to engineering practice.
【作者单位】：江苏大学国家水泵及系统工程技术研究中心;
【基金】：中国博士后科学基金资助项目(2015M581737) 江苏省自然科学基金青年基金资助项目(BK20150508)
【分类号】：O359

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