耦合DEM-CFD法双入口磨粒流动力学模拟及加工试验

针对单入口磨粒流加工装置光整不均匀问题,提出了双入口磨粒流加工装置,为了解决传统CFD软件不能跟踪颗粒撞击壁面问题,结合DEM和CFD方法,通过耦合PFC和CCFD软件,利用DMP颗粒运动模型和标准k-ε湍流模型来模拟磨粒在流场中的运动.仿真中,通过PFC记录磨粒撞击壁面的速度和次数,通过CCFD记录流场运动状态,并应用Abaqus中Johnson-Cook模型分析了撞击速度和撞击次数对靶材质量损失的影响.数值模拟结果表明,双入口装置内两股流体撞击使得磨粒运动更为无序,磨粒撞击壁面次数大大增加,同时撞击壁面速度大于40 m/s的次数达到1 382次,远大于单入口的563次,使得加工面的材料去除速度更快.加工试验结果表明,加工30 h后,双入口装置加工的工件表面粗糙度Ra=0.35 μm,单入口装置工件表面粗糙度Ra=0.65 μm,加工效率明显提高.

Coupling DEM-CFD double inlet abrasive flow dynamics of numerical simulation and test device

Aiming at the uneven finish machining effected by the single inlet abrasive flow peocessing,a double inlet processing was brought forward.In order to solve the processing of particles impact the wall cann＇t be tracked by tradition CFD software,a new method which combined DEM with CFD and through coupling the PFC and CCFD software with DMP particle motion model and standard k-ε turbulence model was used.The speed of abrasive was recorded by PFC and the movement of flow was recorded by CCFD.Johnson-Cook model in Abaqus was used to analyze the effect of impact velocity on the target mass loss.The numerical results indicate that two flow impacts make the abrasive＇s movement more disorder in double inlet processing and the impact between wall and abrasive increase greatly.The speed of impact between abrasive and wall above 40 m/s is 1 382 times in double inlet processing while in single inlet processing is 563 times.Processing test results indicate that the surface roughness of work piece is Ra=0.35 μm in double inlet processing after 30 hours of processing,while in single inlet the value is Ra =0.65 μm which improved the processing efficiency greatly.