椭圆螺旋管道混合器混合效果模拟研究
Numerical Simulation for Mixing Uniformity of Spiral Oval Duct Mixer

应用CFD技术研究了椭圆螺旋流道内两相液体在充分发展条件下的混合效果。基于FLUENT软件，对混合性能进行了数值模拟研究，讨论了椭圆螺旋管道混合器的截面形状、曲率半径、螺距3种因素对该混合器混合效果的影响。模拟所得液相的流动状态与实验结果具有很好的一致性。提取相应截面液体的混合不均匀系数，分析结果表明：截面形状的变化会给螺旋管道混合器造成不同程度的狭小区域，对混合均匀性影响较大；增加螺距会对混合产生消极的影响；当曲径为某一特征值时，混合效果可达到最好状态；同时，通过仿真分析得出，液体流速的改变对混合器中液体的混合效果影响不大；通过对流场内部剪切速率、流线、质点速度场的分析，讨论了粒子无序运动是螺旋混合器内液体充分混合的关键因素。
The two-phase mixing effect of spiral oval mixer was studied with the CFD technology when liquid in duct has insufficient natural flow. The mixing effects on the change of cross-sectional shape, radius of curvature and pitch of mixer were discussed and the cloud chart of the distribution phase was obtained based on the FLUENT software. The simulation results on the distribution of liquid have good adaptability with the experimental results. The data on the COV (Coefficient of variation) of liquid in relevant cross-sectional shape shows that there is a narrow area when the cross-sectional shape changes, producing a big impact to the mixing effect. There is a negative influence if the pitch of spiral oval duct increases; the mixing performance obtains its best state when the radius of curvature has a value. At the same time, simulation results show that the flow rate does not have important mixing effects on the liquid in the spiral oval duct mixer. Based on the previous research, the mixing process of different kinds of liquid in the spiral oval duct mixer was analyzed according to strain rate, the distribution of flow streamline and velocity field of a particle. The key factor of full mixing with the spiral oval duct mixer is that the distribution of particles is not in good order