平流式沉淀池液固两相流力学特性的立面二维数值模拟  

2D vertical plane numerical simulation of solid-liquid two-phase turbulent characteristics in a horizontal sedimentation tank

作　　者：魏文礼[1] 张沛[1] 刘玉玲[1] 

机构地区：[1]西安理工大学水利水电学院,西安710048

出　　处：《应用力学学报》2014年第2期242-245,311-312,共4页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(51178391);陕西省教育厅基金(2010JK761);中央财政支持地方高校发展专项资金特色重点学科项目资助(106-00X101)

摘　　要：采用双流体模型,选取RNG k-?紊流模型封闭双流体两相流时均方程,对平流式二次沉淀池液固两相流力学特性进行立面二维数值模拟。采用有限体积法求解双流体微分方程;紊动能、紊动能耗散率方程均采用Quick离散格式;耦合求解速度与压力时使用了压力隐式算子分裂PISO(Pressure-Implicit with Splitting of Operators)算法。通过模拟表明:水流经过挡板后,底部是急剧扩散的主流,流速大,上部是回流;流速沿流程逐渐减小,到中部近似均匀流;出口附近水流收缩流出,流速变大。进水口附近紊动动能较大,而后紊动动能沿流程逐渐减小,在出水口附近,由于流速的增大紊动动能也随之增大。将模拟值与实测值进行了对比分析发现,流速的最大误差为10%,出口悬浮物相对浓度的最大误差为15%。这表明该模型能够较好地模拟沉淀池中的水力特性分布规律,对沉淀池的设计具有一定的参考价值。A two-phase mixture model is used to study the solid-liquid two-phase turbulent flow and sludgeconcentration distribution in a secondary sedimentation tank. The improved RNG two-equation turbulent model is used to close the two-phase time-averaged equations. The Finite Volume Method is used to discretize the differential equations, the turbulence kinetic energy and the kinetic energy of turbulent dissipation are discretized by the Quick scheme and the coupling velocity and pressure equations are solved by the PISO(Pressure-Implicit with Splitting of Operators) algorithm. By the simulation, the velocity and the turbulent kinetic energy and turbulent kinetic energy dissipation rate and solid distribution in a secondary sedimentation tank are obtained. After the baffle the bottom velocity is large, and the upper part is backflow, the velocity gradually decreases along the flow path, to the central the flow becomes uniform, near the exit the flow becomes contraction flow, and the velocity becomes larger. The water turbulent kinetic energy near the inlet is large, and decreases gradually along the flow path. Near the water outlet, the turbulent kinetic energy increases with the increase of flow velocity. The comparisons of simulation results and measured data show that the maximum error rate of velocity is 10%, and that the maximum error of export suspension relative concentration is 15%, which indicates that the model can well simulate the hydraulic characteristics of sedimentation tanks, and can provide a reference in designing sedimentation tanks.

关 键 词：平流式沉淀池 数值模拟 紊流 水力特性 

分 类 号：O241[理学—计算数学]