空化水喷丸工艺中喷嘴几何参数对空化行为影响的研究
Influence of Nozzle Geometric Parameter on Cavitation Behavior in Water-jet Cavitation Peening Processing

空化水喷丸是利用微小空泡群在固体边界附近溃灭时产生的冲击波压力和微射流来强化金属材料表面,而这些空泡群则是由缩放型喷嘴产生的空化射流所提供。因此,缩放型喷嘴的空化性能可直接影响喷丸效果。利用FLUENT计算软件对缩放型喷嘴产生的淹没式空化水射流进行计算机模拟,并模拟分析了喷嘴喉部直径和喷嘴扩张角对流场中空化行为的影响,同时使用Fujifilm压敏试纸对垂直于空化水射流轴线的截面上的冲击压力场进行测量。结果表明,随着喷嘴喉部直径的增大或喷嘴扩张角的减小,流场中的整体汽含率会升高,试验测得的最高冲击压力高达300 MPa。
Water-jet cavitation peening uses the shock wave pressure and micro-jet produced by the cavitation bubbles collapsing near the surface of materials to strengthen the material surface, the cavitation bubbles are provided by the submerged cavitating water jet generated by convergent-divergent nozzle. Therefore, the cavitation capability of convergent-divergent nozzle can affect the peening effect directly. With using FLUENT software,the computer simulation is applied to study the submerged cavitating water jets, and the influences of nozzle throat diameter and nozzle divergence angle on the cavitation behavior in the flow field are analyzed. The Fujifilm pressure-sensitive paper is applied to measure the pressure distribution on the section which is perpendicular to the axis of cavitating water jet. The results show that the vapor fraction in flow field rises with the nozzle throat diameter increasing or the nozzle divergence angle decreasing, and the measured pressure in the experiment is up to 300 MPa