塔式曝气池内非牛顿活性污泥气液两相数值模拟

发布时间：2018-05-21 02:10

本文选题：数值模拟 + 群体平衡模型　；参考：《中国环境科学》2017年05期

【摘要】：基于欧拉-欧拉架构下,采用欧拉双流体模型耦合PBM(群体平衡模型)对活性污泥这一非牛顿流体下的实验室尺度塔式曝气池气液两相进行数值模拟,探讨不同污泥浓度下,塔式曝气池内气液两相流速度场、气含率、动力黏度等流体动力学行为,发现低速下塔式曝气池内时均气相体积分数分布呈倒梯形柱状,时均流场及速度场均对称分布.随着污泥浓度增大,曝气池中下部气相体积分数高值区面积收窄,液相垂向速度峰值不断增高.低浓度污泥时,x方向液相速度呈现与牛顿流体相似的周期性摆动;污泥浓度越大,曝气池时均气含率越小,以水为介质时会高估曝气池内气含率;污泥浓度为10.2g/L时,动力黏度峰值最大,且曝气池中央黏度低值区呈"V"字形分布.
[Abstract]:Based on the Euler-Euler architecture, the two-fluid model coupled with PBM (population equilibrium model) was used to simulate the gas-liquid two-phase of the laboratory scale tower aeration tank under the non-Newtonian fluid, and the different sludge concentration was discussed. The hydrodynamic behaviors of gas-liquid two-phase flow velocity field, gas holdup and dynamic viscosity in the tower aeration tank are discussed. It is found that the average gas phase volume fraction distribution in the tower aeration tank is inverted trapezoidal at low speed, and the time-averaged flow field and velocity field are symmetrical. With the increase of sludge concentration, the area of high value area of gas phase volume fraction in the middle and lower part of aeration tank is narrowed, and the peak value of vertical velocity of liquid phase is increasing. When sludge concentration is low, the liquid velocity in X direction is similar to that of Newtonian fluid. The higher the sludge concentration is, the smaller the average gas holdup in aeration tank is, the higher the gas holdup in aeration tank is when water is used as medium, and the higher the sludge concentration is, when the sludge concentration is 10.2g/L, The peak value of dynamic viscosity is the largest, and the low value region of central viscosity of aeration tank is "V" zigzag distribution.
【作者单位】：西南交通大学土木工程学院;西安交通大学人居环境与建筑工程学院;
【基金】：国家自然科学基金资助项目(21306145) 国家重大科技专项(2016ZX05011001-002)
【分类号】：X703

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