基于CFD方法的小孔自由射流数值模拟

Numerical Simulation of a Small-Hole Free Jet Flow Field Based on CFD Method

针对流体的小孔喷射问题,采用了计算流体力学(CFD)方法对流体在流过小孔时的自由射流场进行了数值模拟研究。模拟结果表明:在射流场中,主流区中心流体速度高且保持稳定,主流区边壁流体由于与气体摩擦而导致速度急剧下降;在气雾区,流体速度降低而形成气液分散状态;小孔内发生流体加速现象,且随着孔径和流体初速度的增加,小孔内流体的加速度相应增大;流体加速度的变化量随流体初速度的增加逐渐变大,随孔径增加而逐渐减小并趋近于零。本研究得到了低速下小孔喷射状态的模拟模型,以及在不同孔径及初速度下喷射流的演化过程。

The computational fluid dynamics(CFD)method is used for numerical simulation of a free jet of fluid flowing through a small hole.The simulation results show that in the jet flow field,the fluid velocity in the center of the main flow region is high and stable,while the fluid velocity near the side wall of the main flow region decreases sharply due to the friction with the gas.In the aerosol region,the fluid velocity decreases and a gas-liquid dispersion state is formed.The fluid acceleration occurs in the small-hole,and with the increase of the hole diameter and initial fluid velocity,the acceleration of the fluid in the small-hole increases correspondingly.The variation of fluid acceleration gradually increases with the increase of the initial fluid velocity,while decreases with the increase of the hole diameter and approaches zero.In this paper,the simulation model of a small-hole jet at low fluid velocities is established,and the evolution processes of fluid jet at different hole diameters and initial velocities are obtained.