基于剪切应力输运湍流模型的两相磨粒流动力学特性研究

为了解决软性磨粒流加工方法(SAFM)中磨粒流动力学特性难以进行实验的问题，提出一种基于剪切应力输运(SST)湍流模型的数值模拟研究方法。该模型继承了k-ω模型和标准k-ε模型的优点，对近壁区有较高的仿真精度。利用SST湍流模型与流体混合模型相结合的方法，以工程中常见的U形流道作为数值模拟对象，对磨粒流动力学特性进行研究。分析数值模拟结果，得到流道内磨粒流的压力和速度的分布规律：楔形流道内，磨粒流的压力相对于等截面流道明显增大，并且楔形流道内湍流程度一直处于发展状态。设计了颗粒轨迹观测实验平台，基于该平台对流道内颗粒轨迹进行研究发现：虽然流体在壁面处的速度为0，但流体中的颗粒依然对壁面产生碰撞。通过理论与实验研究，揭示了流道内两相磨粒流动力学特性，为软性磨粒流加工提供了理论基础，并提供了约束模块的设计方法。

Study on Dynamic Characteristics of Two-phase Abrasive Flow Based on Shear Stress Transport Turbulent Model

In order to bypass difficulties in experiment of soft abrasive flow dynamic characteristics,a method based on shear stress transport(SST) turbulent model was proposed.It has both advantages of k-ω and standard k-ε models and higher simulation precision in the near wall region.As a common structure in engineering,a U-shaped channel was taken as a research object,and the soft abrasive flow dynamic characteristics were analyzed by using the method of combining SST turbulent model and mixture model.The pressure and velocity distributions of the abrasive flow in channel were obtained by analyzing the numerical simulation results.A test-bed was designed to observe the track of particles in the channel.It is found that,although the velocity of fluid on the wall surface is zero,the particles in fluid still impact the wall.The theoretical and experimental researches reveal the dynamic characteristics of abrasive flow in channel and provide a foundation for the abrasive flow machining and the design of restrictive components.