新型射流气泡发生器的设计与数值模拟

Design and Numerical Simulation of a New Jet Bubble Generator

为了提高微细粒矿物的矿化效果,设计了一种含有振荡腔的新型气泡发生器,并将引入气液两相流可以在较低音速下流速实现超音速流动的理念。通过理论计算得出:在工作压强为0.1MPa,气液体积比为1∶1的条件下,气液两相流混合体达到超音速流动的临界流速为20 m/s。运用Fluent软件对新型气泡发生器进行气液两相流数值模拟,得到了其内部流体的速度和体积分布规律。模拟结果显示,液相最高速度为20.7m/s,气相最高速度为24.2m/s,但是只有在气含率达到50%左右时,才能在扩散管末端产生激波振荡现象。这说明气液两相流超音速流动不仅和速度有关,也和两者之间的比例有关。超音速流动的过程中会伴有激波的产生,可以形成能量较高的湍流,使气相和液相充分混合,提高矿化效果。

In order to improve the mineralization effect of fine-grained minerals,a new bubble generator with oscillating cavity was designed,and the idea that two-phase flow can realize supersonic flow at low velocity was introduced into it.Through theoretical calculation,the critical velocity of supersonic flow of gas-liquid two-phase mixture was 20m/s under the conditions of working pressure of 0.1MPa and gas-liquid volume ratio of 1∶1.Then,the new bubble generator was numerically simulated by Fluent software,and the velocity and volume distribution law of its internal fluid was obtained.The simulation results show that the highest velocity of liquid phase is 20.7m/s and the highest velocity of gas phase is 24.2m/s,but only when the gas holdup reaches about 50%,the shock wave oscillation can occur at the end of the diffuser.This shows that the supersonic flow of gas-liquid two-phase flow is not only related to velocity,but also to the mixing ratio between them.In the process of supersonic flow,there will be a shock wave,which can form a turbulent flow with high energy,so that the gas phase and the liquid phase can be fully mixed,improving the mineralization effect.