叶片浸入深度对搅拌机内部流场影响仿真

为了研究叶片浸入深度对搅拌机内部流场的影响规律。应用Fluent计算流体动力学软件对搅拌机内部流场进行三维数值模拟,采用非结构化四面体网格,利用多重参考系方法,选用非稳态Mixture多相湍流计算模型,分析了搅拌机内部流体浓度、速度和湍动能等参数随叶片浸入深度不同而产生的变化和分布情况,揭示其内部的流动规律。模拟结果表明:中心搅拌机械在叶片轴线下方存在流动呆滞区,造成混合不畅;叶片的浸入深度对搅拌机内部湍动能值影响较小,但是对其固相分布却产生重要影响,因此要合理选择叶片的浸入深度;叶片的浸入深度等于液体高度的1/2,能够达到最佳的混合效果。研究结果对于揭示搅拌机械内部流场的流动规律,以及设备的优化设计和运行管理提供了参考依据。

Numerical Simulations on Effects of Submerged Depth of Vanes on Flow Field in Mixing Machine

In order to investigate the effects of the submerged depth of vanes on the flow field in a mixer,a three-dimensional numerical model was developed to simulate the internal flow field in a mixer using computational fluid dynamics software called Fluent.The numerical simulation used the unstructured tetrahedron grids,multi-reference frame,and unsteady Mixture multiphase turbulent calculation model to analyze the variation and distribution of the concentration,speed,and turbulent kinetic of the internal fluid in the mixer under the changes of the submerged depth of vanes,thereby revealing the characteristics of the internal flow in the mixer.The simulation results showed that the central mixing machine has a flow dull area below the axis of the vanes,which can block the mixing process.Also,the submerged depth of vanes had insignificant effects on the internal turbulent kinetic values in the mixer;however,it can have significant effects on the solid phase distribution.Therefore,the submerged depth of vanes needs to be selected reasonably.The mixer can have the best mixing effects when the submerged depth of vanes is half of the liquid height.The simulation results can provide reference information for the optimization of the equipment design and operation management given that the internal flow in the mixer can be characterized using the numerical simulation.