氧化沟及水解酸化池数值模拟研究

发布时间：2018-03-24 07:30

本文选题：氧化沟　切入点：水解酸化池　出处：《清华大学》2015年硕士论文

【摘要】：工农业发展给人类生活生产带来了极大便捷,同时也引发了一系列污染问题,如水污染、空气污染等。近年来,为了保护水资源、防治水污染,污水处理工程技术得到快速发展,氧化沟工艺与水解酸化工艺因其便捷、高效、实用等优势而被广泛应用。污水处理过程中,反应器内的流体运动直接影响混合效果,因此,深入研究污水处理反应器内的流场特性对提高污水处理效率具有重要意义。在这一背景下,本文针对氧化沟及水解酸化池污水反应器,应用Gambit软件建立几何模型,并用Fluent软件进行数值模拟,计算污水处理器内部的流场及污泥浓度场,确定了污泥沉积区与漂浮区。主要研究方法与结论如下:针对氧化沟的结构特点,运用计算流体力学知识,采用标准k??紊流模型,建立了三维数学模型并进行了计算。首先,对一组转盘在清水中运行的情况进行数值模拟,将得到的流速模拟值与试验实测值进行对比分析。结果表明,模拟值与实测值吻合较好,能够反映出氧化沟内的流场特性,验证了所建立的数值模型具有较高的准确性。基于上述模型,根据转盘个数、水中是否有污泥进行了数值模拟,研究氧化沟内的流场分布以及污泥浓度分布,分析水中污泥的混合状态,由此确定氧化沟内容易出现污泥沉积或者漂浮的区域。比较一组转盘和两组转盘运行情况,当两组转盘同时运行时,氧化沟中流速较大,水流循环加快,水中污泥混合效果更好。另一方面,对于水解酸化工艺,本文结合吉林省某污水处理厂的水解酸化池进行了研究。该池由于搅拌机受到腐蚀损坏,池内污泥淤积严重。文中对原有蛇形水解酸化池的流场及污泥淤积进行了数值模拟,并用现场观测数据进行了验证;同时,对其改造方案——升流式水解酸化池进行了污泥运动模拟。计算结果表明,升流式水解酸化池能够满足水解酸化工艺要求,充分提高污水处理效果。上述两方面的数值计算结果表明,针对氧化沟及水解酸化池建立的数值模型,能较好地反映内部流场特性及污泥分布,为其设计运行提供科学依据。同时,本文研究表明数值计算能够有效模拟污水反应器的流体力学特性,对于相关反应器的设计、运行、优化等环节具有一定的指导意义。
[Abstract]:The development of industry and agriculture has brought great convenience to human life and production, but also caused a series of pollution problems, such as water pollution, air pollution, etc. In recent years, in order to protect water resources and prevent water pollution, Wastewater treatment engineering technology has been developed rapidly, oxidation ditch process and hydrolytic acidification process have been widely used because of their advantages such as convenience, efficiency, practicality, etc. In the process of sewage treatment, the fluid movement in the reactor directly affects the mixing effect. It is important to study the characteristics of flow field in sewage treatment reactor to improve the efficiency of wastewater treatment. Under this background, the geometric model of wastewater treatment reactor in oxidation ditch and hydrolytic acidification tank is established by using Gambit software. The flow field and sludge concentration field in the sewage processor were calculated by using Fluent software. The sludge deposition area and the floating zone were determined. The main research methods and conclusions are as follows: according to the structural characteristics of oxidation ditch, Use computational fluid mechanics knowledge, adopt standard k? ? In the turbulent model, a three-dimensional mathematical model is established and calculated. Firstly, a group of rotating discs running in clear water are numerically simulated, and the simulated velocity values are compared with the experimental measured values. The results show that, The simulated values are in good agreement with the measured values, which can reflect the characteristics of the flow field in the oxidation ditch, and verify the accuracy of the established numerical model. Based on the above model, and according to the number of turntable, whether there is sludge in the water is numerically simulated. The flow field distribution and sludge concentration distribution in oxidation ditch were studied, and the mixed state of sludge in water was analyzed. When the two sets of turntables are running simultaneously, the flow rate in the oxidation ditch is higher, the flow cycle is faster, and the sludge mixing effect in the water is better. On the other hand, for the hydrolytic acidification process, In this paper, the hydrolytic acidification tank of a sewage treatment plant in Jilin Province was studied. The sludge deposition in the tank was serious due to the corrosion damage of the mixer. The flow field and sludge deposition of the original serpentine hydrolytic acidification pond were numerically simulated in this paper. At the same time, the sludge motion of up-flow hydrolysis acidification tank was simulated. The result shows that the up-flow hydrolysis acidification tank can meet the requirements of hydrolytic acidification process. The numerical results from the above two aspects show that the numerical model for oxidation ditch and hydrolytic acidification tank can well reflect the characteristics of internal flow field and sludge distribution. At the same time, the numerical calculation can effectively simulate the hydrodynamic characteristics of the wastewater reactor, which has certain guiding significance for the design, operation and optimization of the relevant reactors.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

【相似文献】