后混合水射流喷丸喷头内流数值模拟

Numerical simulation of nozzle inside-flow of rear-mixed water jet shot peening

为研究玻璃珠弹丸在后混合水射流喷丸喷头内的运动轨迹和速度特性,根据液固两相流动的拉格朗日离散相模型,应用FLUENT软件对喷头内液固湍流进行了数值模拟,得到了连续相的轴向速度和轴向动压强,获得了弹丸的运动轨迹和弹丸的轴向速度随行程及时间的变化规律。结果表明,连续相在喷头混合室入口处存在环形回流区,在混合室内呈非对称流动;弹丸在喷头内的轴向速度沿行程分为4个阶段,依次是弹丸在混合室内的回流段、弹丸第1次加速段、弹丸在环形回流区的减速段和弹丸第2次加速段,其在弹丸喷嘴出口截面上靠近轴心的轴向速度达到连续相轴心最大轴向速度的94.77%。

To study the movement trace and the velocity characteristic of beading pill in rear-mixed water jet nozzle,according to the Lagrange discrete phase model of the liquid-solid two-phase flow,a numerical simulation of liquid-solid turbulent flow was conducted in nozzle with fluent software.The axial velocity and the axial dynamical pressure of the continuous phase were obtained as well as the pill＇s movement trace and the change rule of the pill＇s axial velocity along with the traveling schedule and the time.The results indicate that the circumfluence region exists in the entrance of the nozzle mixture chamber,and the asymmetrical flowing in the chamber,that there are four stages of the axial velocity of the pill in the nozzle,called the pill backflow in the mixture chamber,the pill first acceleration section,the pill deceleration section in the circumfluence region and the pill second acceleration section,and that the axial velocity of the pill which is located in the nozzle exit section near the axes is 94.77% of the biggest axial velocity of continuous phase axis.