Abstract: Aiming at the problems of uneven surface roughness Ra after abrasive flow machining of titanium alloy workpieces with complex curved surfaces, a profiling constrained flow channel with disturbance structure for machining was proposed. Combining with SST k-ω turbulence model, discrete phase model（DPM）and Oka erosion model in computational fluid dynamics（CFD） software, the dynamics characteristics of abrasive flow for original flow channel and five kinds of disturbance flow channels with different disturbance angles were analyzed. The simulation results show that abrasive flow in the disturbance flow fields has greater turbulent kinetic energy，dynamic pressures and erosion rates on the workpiece surfaces than that of the original flow field without disturbance structures, and the erosion effects are the best when the disturbance angle is as 30°. The abrasive flow machining platform was built and the original flow channel and 30° disturbance flow channel were used for the machining tests based on simulation conditions. The testing results show that the surface roughness value Ra with different curvatures regions of workpieces are dispersed by using the original flow channel after 5 h machining, and the machining effectiveness is uneven, while the surface roughness value Ra of different workpiece regions has better uniformity by using disturbance flow channels after 5 h machining.

Key words: titanium alloy surface, abrasive flow machining, disturbance flow channel, surface erosion, machining uniformity

摘要： 针对具有复杂曲面的钛合金工件磨粒流抛光后表面粗糙度Ra不均匀问题，提出一种具有扰流结构的仿型约束加工流道。借助计算流体动力学（CFD）分析软件，结合SST k-ω湍流模型、离散相模型（DPM）和Oka冲蚀模型，仿真分析原始流道和5种不同扰流角度的扰流流道内磨粒流动力学特性。数值模拟结果表明：扰流流场中的磨粒流相较于原始流场在工件表面具有更大的湍流动能、动压力和冲蚀速率，其中扰流角度为30°时冲蚀均匀性较好。基于仿真条件搭建了磨粒流加工试验平台，使用原始流道和30°扰流流道分别进行了加工试验。试验结果表明：使用原始流道加工5 h后，工件表面曲率不同区域的表面粗糙度Ra值分散，加工效果均匀性较差；使用扰流流道加工5 h后，工件表面各区域表面粗糙度Ra的均匀性明显优于无扰流流场的加工均匀性。

关键词: 钛合金曲面, 磨粒流加工, 扰流流道, 表面冲蚀, 加工均匀性