搅拌过滤过程的CFD仿真

CFD Simulation in the Process of Stirring and Filtering

螺旋搅拌过滤器的搅拌轴转速直接影响过滤过程的过滤效果。文中采用计算流体力学的方法对过滤器的工作过程进行仿真。分析了过滤过程中,搅拌腔内流体的流速、流态、压力和固含量随搅拌轴转速的影响,讨论了流场内截面的切向流速大小随工作转速的变化规律、各截面涡流的形成和对过滤效率的提高作用,以及工作转速对分离效率的影响。结果表明,随工作转速从200 r/min增加到800 r/min过滤腔内切向流速上升近4倍,边界压力上升15%,分离效率提升5.3%;域内各截面涡流数目增加、涡流直径变大,对混合液的过滤效果增强。文中还给出了螺旋搅拌过滤设备的过滤方程,方程的计算值与仿真值的误差在15%左右,可以为后续设备的结构优化和改进提供必要的依据。

The agitation shaft rotation speed of the spiral stirring filter directly influences filtration effect in the filter process. This paper adopts the method of computational fluid mechanics to make simulation of the work process of filter. We analyze the influence of flow velocity, flow regime, pressure, and solid content by agitation shaft rotation speed in stirring cavity, and discuss change law of tangential flow velocity in flow field section with tangential flow velocity, the formation of eddy in all the sections, the improvement effect to filter efficiency and as well as the influence of separation efficiency by working speed. The result manifests that, as its working speed adds from 200r/min to 800r/min that tangential flow velocity in filtration cavity improve by four times, boundary pressure rises 15% and separation efficiency rises 5.3%; the increase of eddy number in all sections intra-area and the enlarge of the eddy diameter enhances the filtration effect of mixed liquor. This paper also gives the filtration equation of sugarcane filtration set. The error between calculated value and simulation value is about 15%, which can provide necessary evidence for follow-up structure optimization and improvement of equipment.