弧叶搅拌器不同桨叶直径下混合性能受转速和高度的影响程度分析

Analysis of the influence of rotational speed and height on the mixing performance under different blade diameters of arc-blade agitator

为了探究转速和安装高度对不同搅拌桨直径混合性能的影响程度,以弧叶搅拌器为研究对象,采用Realizablek-ε湍流模型和欧拉多相流模型进行数值计算,对比分析了不同搅拌桨直径在不同安装高度和转速下的混合时间、单位体积混合能、功率、固相颗粒分布、湍动能以及速度流场分布情况。结果表明:当搅拌桨直径增加时,转速对混合时间和固相颗粒运动的影响程度先减小后增加,对功率、湍动能以及介质流速的影响程度增加,对单位体积混合能无明显影响;当搅拌桨直径增加时,安装高度对混合时间和固相颗粒运动的影响程度先减小后增加再减小,搅拌桨直径为400mm时影响程度最大,对功率、湍动能以及介质流速无明显影响;当安装高度低于H/3时,随着搅拌桨直径的增加,高度对单位体积混合能的影响程度先增加后减小,反之,高度对单位体积混合能的影响程度增加。该研究可以在一定程度上说明搅拌桨直径在设计参数发生变化时对流场的影响程度,能够为机械搅拌提供理论指导,具有一定的工程应用意义。

In order to explore the influence of rotational speed height and installation on the mixing performance of different impeller diameters,the Realizable k-εturbulence model and the Euler multiphase flow model were used for numerical calculation.The mixing time,mixing energy per unit volume,power,solid particle distribution,turbulent kinetic energy and velocity flow field distribution of different impeller diameters at different installation heights and rotational speeds were compared and analyzed.The results showed that when the diameter of the impeller increased,the influence of the rotational speed on the mixing time and the movement of the solid particles decreased first and then increased,and the influence on the power,turbulent kinetic energy and medium flow rate increased,and there was no obvious effect on the mixing energy per unit volume.When the diameter of the impeller increases,the influence of the installation height on the mixing time and the movement of the solid particles decreased first,then increased and then decreased.When the diameter of the impeller was 400mm,the influence was the greatest,and there was no significant effect on the power,turbulent kinetic energy and medium flow rate.When the installation height was lower than H/3,the degree of influence of height on the mixing energy per unit volume increased and then decreased as the diameter of the mixing paddle increased,and conversely,the degree of influence of height on the mixing energy per unit volume increased.On the contrary,the influence of height on the mixing energy per unit volume increased.This study can explain the influence of the impeller diameter on the flow field to a certain extent when the design parameters changed.It could provide theoretical guidance for mechanical stirring and had certain engineering application significance.