超临界CO2磨料射流流场影响因素的模拟分析

为了揭示超临界CO₂磨料射流流场特性，利用计算流体动力学模拟软件，对超临界CO₂磨料射流结构及不同因素对射流流场的影响规律进行了研究。结果表明:超临界CO₂磨料射流轴向速度和冲击力随着喷距的增大，先增大后减小，即存在最优喷距，喷射压差为10~30 MPa时最优喷距为3~6倍喷嘴直径；喷射压差一定时，围压由10 MPa增至30 MPa对射流速度场及液相冲击力会造成较小的负面影响。通过超临界CO₂射流破岩实验对上述2因素进行了辅助对比验证；流体温度由333 K增至413 K，固液两相轴向速度增大，而流体密度降低，导致液相冲击力减弱；磨料浓度由3.0%连续增至11.0%，射流固液两相轴向速度逐渐降低，降幅逐渐减小。

A simulation analysis of factors influencing the flow field of the abrasive supercritical CO2 jet

To confirm and reveal the characteristics of the flow field of the abrasive supercritical CO₂ jet, the structure of the jet and the influence of the ambient factors were analyzed through numerical simulation, with the computational fluid dynamics software. Results show that the axial velocities of the fluid and particles on the wall firstly increase and then descend as the standoff distance increases, as well as the impact pressure of the fluid, which means that there is an optimal standoff distance where their peak values exist respectively and it is 3-6 times of the jet nozzle diameter at the differential pressure of 10-30 MPa; given fixed jet differential pressure, increase of the confining pressure from 10 MPa to 30 MPa has a weak negative effect on the axial velocity of the jet fluid. The supercritical CO₂ jet-breaking-rock experiment was conducted to provide test to the results of the numerical simulation. The velocities of the fluid and particles increase as the temperature goes up from 333 K to 413 K, while the impact pressure of the supercritical CO₂ fluid becomes weaker because of fluid density decrease as the volume fraction of the abrasive particles is set from 3.0% to 11.0% in a row, the velocity of each phase gradually decreases and the variation gradually gets smaller.