摘要
建立了前混合磨料水射流喷嘴物理模型。基于FLUENT软件,采用颗粒轨道模型、Grant弹性恢复系数和E/CRC磨损模型对磨料水射流喷嘴内的磨损特性进行了数值模拟。结果表明:当喷嘴收缩角为20°以上时,喷嘴磨损呈现两个严重磨损区,分别在喷嘴圆柱段入口处前较短距离范围内和喷嘴圆柱段出口处前较短距离范围内;随着喷嘴收缩角的增大,磨料颗粒与喷嘴圆柱段壁面碰撞次数和速度增加,同时随着喷嘴长径比的增大,喷嘴圆柱段壁面磨损速率整体增加,严重磨损区范围扩大,结果均使喷嘴圆柱段的磨损加剧。以喷嘴壁面磨损速率的面积加权平均积分表征喷嘴整体的磨损程度。随着收缩角和长径比的增大,喷嘴壁面磨损速率的面积加权平均积分增大,喷嘴的磨损整体而言越严重。因此,从减小喷嘴磨损的角度而言,喷嘴的收缩角和长径比宜取小值。
Physical model of pre-mixed abrasive water jet nozzle is established. Based on the software of FLUENT, numerical simulation of wear characteristic of abrasive water jet nozzle was carried out by use of particle trajectory model, Grant collision elastic recovery coefficients and E/CRC erosion model. The simulation results show that there are two severe wear sections for nozzle wear, lo- cating within a short distance range before the entrance of cylindrical section of nozzle and before the exit of cylindrical section of nozzle respectively, when the contract angle of nozzle is above 20°. The collision frequency and velocity of abrasive particle with the wall of cylindrical section of nozzle increase with the increase of contract angle of nozzle. At the same time, wear rate of the wall of cylindrical section of nozzle increases integrally and the range of severe wear section expands with the increase of the ratio of cylindrical section length to exit diameter of nozzle. These cause the wear of cylindrical section of nozzle aggravating. The overall wear degree of the nozzle is characterized by the area-weighted average integral of nozzle wall wear rate. The area-weighted average integral of nozzle wall wear rate increases, namely the overall wear degree of the nozzle is more serious with the increase of contract angle and the ratio of length to diameter of nozzle. Therefore, the contract angle and the ratio of cylindrical section length to exit diameter of nozzle is selected small for better from the point of view of reducing the wear of the nozzle.
出处
《机床与液压》
北大核心
2017年第23期146-149,171,共5页
Machine Tool & Hydraulics
基金
总后勤部军需物资油料部项目(YX213C208)
重庆市基础科学与前沿技术研究资助项目(cstc2017jcyj AX0166
cstc2016jcyj A0095
cstc2015jcyj B90001)
关键词
磨料水射流
喷嘴磨损
数值模拟
收缩角
长径比
Abrasive water jet, Nozzle wear, Numerical Simulation, Contract angle, Ratio of length to diameter
