为分析解决高速运动的磨料粒子对喷嘴内部的冲蚀，以提高其抗冲蚀磨损效果，优化设计超高压射流喷嘴结构，采用瞬态两相流仿真与离散相仿真并进行可视化处理，模拟冲蚀试验。建立喷嘴内轴对称固液两相流分析模型，对喷嘴内部预混合磨料水射流粒子的运动轨迹和加速过程进行模拟，计算喷嘴内壁最大冲蚀率，并优选喷嘴内部结构。结果表明：石榴石磨料粒子在碳化钨喷嘴聚焦段与喷嘴内壁发生碰撞并被反射回轴线产生聚焦效应，粒子运动速度降低并对内壁产生冲蚀。最大冲蚀位于喷嘴收缩段与聚焦段连接处，最大冲蚀率为1.9×10-6 kg/(m2·s)；第2峰值点则出现在聚焦段中前部，距喷嘴出口20 mm处，冲蚀率为1.7×10-6 kg/(m2·s)。根据喷嘴实际试验寿命和失效准则，求得实际喷嘴冲蚀率为1.078×10-6 kg/(m2·s)，冲蚀率修正系数为0.567 4。通过有限元分析对喷嘴造型的优化提供了选择依据，有利于提高喷嘴耐蚀性。
In order to analyze and solve the erosion of the inside of nozzle caused by high - speed abrasive particles for improving the nozzle’s erosion and wear resistances and optimizing the structure design of ultra - high pressure jet nozzle, transient two - phase flow simulation, discrete phase simulation and visualization processing were used to simulate the erosion test. An axisymmetric solid - liquid two - phase flow analysis model was established for the inside of the nozzle, and the motion trajectory and acceleration process of the premixed abrasive water jet particles in the nozzle were simulated. Meanwhile, the maximum erosion rate of the nozzle inner wall was calculated, and the internal structure of the nozzle was optimized. Results showed that the garnet abrasive particles collided with the inner wall of the nozzle in the focusing section of the tungsten carbide nozzle and were reflected back to the axis to cause a focusing effect, the particle movement speed decreased and the inner wall was eroded. Furthermore, the maximum erosion rate was 1.9×10-6kg/(m2·s), which arose at the junction between the contraction section and focusing section of the nozzle. The second peak appeared in the middle and front of the focusing section, 20 mm away from the nozzle outlet, and the erosion rate was 1.7×10-6kg/(m2·s). According to the actual test life and failure criterion of nozzle, the calculated actual erosion rate of the nozzle was 1.078×10-6kg/(m2·s) and the correction coefficient of erosion rate was 0.567 4. Generally, the finite element analysis provided a basis for the optimization of the nozzle shape, which was beneficial for the improvement of the corrosion resistance of the nozzle.
