鼓泡流化床流动特性的欧拉-离散单元方法模拟

Numerical Simulation of Hydrodynamics in a Bubbling Fluidized Bed by Eulerian-Discrete Element Method

利用欧拉 离散单元方法对气固射流流化床内的流体动力学特性进行了数值模拟.在模型中把气相作为连续介质处理,采用欧拉方法建立其动量及质量守恒方程;对固体颗粒相则采用属于拉格朗日范畴的离散单元方法(DEM)模拟;气固两相之间的相互作用采用DiFelice经验关系式反映.利用该模型模拟了流化床内初始阶段的气固两相流动特性.此外,由于气泡特性对流化床的流化质量具有重要的影响,故利用频谱分析理论对床内的模拟压力信号时间序列进行了分析,得出了在几个典型入口气速下的气泡统计生成频率.数值模拟结果与有关实验结果定性一致.

Hydrodynamic characteristics under various fluid velocities in a gas solid bubbling fluidized bed were numerically simulated by Eulerian-discrete element method (DEM), in which, gas phase was still regarded as continuous medium and its governing equations were established based on Eulerian method, but solid phase was simulated based on DEM belonging to Lagrangian method. The interaction between gas and solid phase was calculated by means of empirical correlation proposed by Di Felice. Because the fluidization quality was affected greatly by the bubble characteristic in bed, the pressure signal serial from numerical simulation was analyzed based on frequency spectrum analysis theory and the statistical bubble formatting frequency was obtained. Theoretical results are in qualitative agreement with related test results.