利用计算流体力学模拟技术对某水解酸化池的改进

利用计算流体力学模拟技术，采用三维、稳态、k-ε紊流模型，结合多重参考系模型、弥散相模型及组分输运和化学反应模型，对江苏某污水处理厂水解酸化池进行了模拟。结果表明：水解酸化池内流速分布很不均匀；池内存在大片回流区域以及流速几乎为零的区域，区域总体积占池容的50%以上；平均水力停留时间约为1 480 s，远达不到设计值。结合模拟结果，提出了改进方案。改进后的模拟结果表明：水解酸化池内水流流速分布均匀性大大提高；大片的回流区域消失，速度几乎为零的区域面积也大大减小；水解酸化池的空间得到充分利用，水下推进器的作用也更加明显；平均水力停留时间约为15 340 s，和设计值十分接近。但是仍存在一些不足：水流流速分布的均匀性仍存在一定缺陷；只考虑了单相流，没有考虑池中污泥的作用。

Improvement of a hydrolysis acidification pool using computational fluid dynamics simulation technique

A certain hydrolysis acidification pool is simulated by employing the computational fluid dynamics(CFD) simulation technique based on the adoption of the three-dimensional model under steady,k-ε turbulent state,combined with other models such as multiple reference frame model,discrete phase model and the model of species transport and reaction.The results show that the flow rate distribution is non-uniform;there exists more than 50% of the total pool volume for the big zone of swirling flow and the zone of virtually zero flow velocity.The average residence time for the water is about 1 480 s,which is far below the designed value.With the consideration of the simulation results,an improvement program is proposed.Simulation of the proposed program indicates that the improvement of flow rate distribution results from the disappearance of the swirling flow and the great reduction of the zone of virtually zero flow velocity.Therefore,the effective space of the pool is available,the underwater propeller works more efficiently and the average residence time for the water thus reaches 15 340 s,which is very close to the designed value.However,consideration of single phase flow only and the ignorance of the sludge behavior may affect the simulation results of the distribution uniformity of the flow rate.