摘要
针对后混合磨料射流中固液两相混合不均匀及能量密度低的问题,采用CFD-DEM耦合数值模拟方法,对流体相速度分布、离散相运动轨迹及固液两相混合特性进行了分析。经过试验对比验证,结果表明,磨料在混合腔内的浓度分布呈现两端高、中间低的特点;当射流速度不足以克服腔内涡流影响时,磨料易发生堵塞,影响其运动性能。在理想条件下,磨料与水射流核心碰撞后不与壁面发生大角度碰撞。当入口速度为150,600 m/s时,在喷嘴内停留最短的磨料占比56%;但当入口速度为600 m/s时,磨料在聚焦管内的聚散现象明显,导致能量利用率较低。聚焦管内,磨料在射流作用下发生周向运动,在150 m/s工况时切向速度可达2.12 m/s。延长聚焦管长度能够有效降低切向速度,提升射流加工效率,其中以60 mm的聚焦管长度为最佳。所得结果可为磨料射流喷嘴的优化设计及应用提供参考。
For the problem of uneven solid-liquid two-phase mixing and low energy density in the post-mixed abrasive jet,the CFD-DEM coupled numerical simulation method was adopted,the fluid-phase velocity distribution was analyzed,and discretephase trajectory and solid-liquid two-phase mixing characteristics were analyzed.After experimental comparison and verification,the results show that the abrasive particle concentration in the mixing chamber is higher at both ends and lower in the middle.When the jet velocity is insufficient to overcome vortex effects,particle blockage occurs,impairing their movement.Under ideal conditions,abrasive particles collide with the water jet core without large-angle collisions with the wall.At inlet velocities of 150 m/s and 600 m/s,56%of the abrasive particles have the shortest residence time in the nozzle.However,at 600 m/s,particle aggregation and dispersion are more pronounced,resulting in lower energy efficiency.Inside the focusing tube,particles exhibit circumferential motion,with a tangential velocity of 2.12 m/s at 150 m/s.Increasing the focusing tube length can reduce tangential velocity and improve machining efficiency,among them,the 60 mm length is the optimal length.These findings can provide guidance for optimizing abrasive water jet nozzle design and application.
作者
高启强
侯文江
方珍龙
GAO Qiqiang;HOU Wenjiang;FANG Zhenlong(State Key Laboratory of Maritime Technology and Safety,Wuhan University of Technology,Wuhan 430063,China;Sanya Science and Education Innovation Park of Wuhan University of Technology,Sanya 572025,China)
出处
《流体机械》
CSCD
北大核心
2024年第12期70-78,共9页
Fluid Machinery
基金
国家自然科学基金青年项目(51706161)
海南省重大科技计划项目(ZDKJ202015)。
