曝气池内气液混合液两相流力学特性的数值模拟

采用欧拉-欧拉多相流模型和标准k-ε湍流模型对曝气池内气液两相流力学特性进行数值模拟研究。速度与压力的耦合求解采用了Phase-Coupled-SIMPLE算法。对中心截面(y=0.025 m)在(z=0.71 m)测线上垂向速度的模拟值与实验值进行比较分析,结果吻合较好。结果表明:当表观气速较小时,进口气速对曝气池上方混合液的垂向速度影响较小;当表观气速较大时,整个曝气池中心截面(y=0.025 m)呈现中心垂向速度大,靠近两侧边壁的垂向速度小,且为负值的规律。并且发现气泡在上升的过程中由于附壁效应容易产生摆动,表观气速越大,附壁效应越明显。通过对曝气池内不同气体速度下池内力学特性的分析研究,以期对曝气池的设计运行提供参考。

Numerical simulation the hydraulic characteristics of gas-liquid two-phase mixture flow in an aeration tank

The paper used Euler-Euler multi-fluid model and standard turbulence model to simulate the mechanical property of gas-liquid mixture in an aeration tank. The coupling solution of velocity and pressure used Phase-Coupled-SIMPLE algorithm.The following results are that the comparison results of simulated vertical velocity and the experimental data along the line z=0.71m in the center section(y=0.025m) are in good agreement.the inlet gas velocity has less impact on the vertical speed of upper mixture fluid in the aeration tank when the uperficial gas velocity is smaller.But when the superficial gas velocity is larger,the middle section of the whole aeration tank shows the law that the vertical velocity close to the center is great, and that close to both side walls is small and negative values.The rising bubbles can easily appear swing due to wall attachment effect, and the greater the superficial gas velocity, the more obvious is the wall attachment effect. The analysis result of mechanical properties in the aeration tank at different gas velocities can provide some reference value for the design and operation of aeration tank.