氧化沟水力学特性研究及结构优化

发布时间：2017-12-28 18:44

本文关键词：氧化沟水力学特性研究及结构优化　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：氧化沟有不少优势：具有抗冲击性、出水水质优良、操作成本低等,在污水处理中的应用也越来越广泛。西安某污水处理厂在运行过程中存在一些问题,本文通过对氧化沟水力学特性等进行研究,对其结构进行优化调整,本文主要包括：(1)自主设计并建立了一套小试氧化沟装置,运用粒子图像测速仪(PIV)测试了作为推流机的潜水泵前端的流场,分析其周围流场的特点,并验证了推流机简化模型的可靠性,60 W潜水泵前端所产生流场的速度最大值约为1.5 m/s。以木屑作为示踪粒子,通过C语言编程,分析研究填料堆积前后过水口表面流场。在对过水口填料堆积问题数值模拟分析和结构优化的基础上,通过小试氧化沟实验装置,完成了过水口填料堆积实验,实验结果显示：实际工程上,潜水推流机安装的位置与过水口的距离应小于7.2 m,可以通过改变潜水推流机安装的位置y偏移量来缓解填料堆积问题,氧化沟过水口不发生填料堆积问题,需保持两池低液位差运行,液位差应保持在0.72 m以下。添加挡板能降低填料的堆积率,在不同程度上缓解填料堆积的问题。小试装置上,当两池液位差为20 mm时,添加挡板能将填料的最大堆积率由16%降低到3.6%；当两池液位差为30 mm时,添加挡板,填料的最大堆积率由31%降低到16.8%。在两池液位差为40 mm时,添加挡板能将填料的最大堆积率由35%降低到18%。(2)用CFD软件对1：36尺寸的小试氧化沟三维数值计算。在小试尺寸氧化沟上进行填料堆积问题的结构优化,用于指导实验研究,发现：最优的参数条件是：5号推流机位置变化n+20 mm,Z:+20 mm；挡板倾角7.5。；挡板逆时针45。开孔。添加逆时针45。开孔倾角7.5。的挡板,能将中部的切向速度由逆流速度0.05 m/s变为顺流速度0.1 m/s,并且上、中部最大法向速度明显降低,能缓解过水口填料堆积问题。(3)用CFD软件对全尺寸氧化沟三维流场数值模拟计算,选取部分截面,分析其水力学特性,并对实际工程中存在的过水口填料堆积问题和能量配置问题进行了分析。重点对能量配置等问题作了优化调整,设计了六种工况条件,发现：在距离弯道出口1.5m处、弯道进口7.5 m处各设置一台推流机,安装位置向内侧平移0.25 m,向上平移0.25m,设置单台推流机功率2.3 KW,6台,功率配置为：4.84 W/m3,效果最好。
[Abstract]:Oxidation ditch has many advantages, such as impact resistance, excellent water quality, low operating cost, and more and more widely used in sewage treatment. A sewage treatment plant in Xi'an there are some problems in the operation process, based on the research of oxidation ditch hydraulic characteristics, to adjust and optimize the structure, this paper mainly includes: (1) designed and established a small oxidation ditch device, using particle image velocimetry (PIV) as the test flow submersible pump the front push flow machine, analysis of flow field around its characteristics, and verify the reliability of the simplified model of flow machine, 60 W submersible pump front generated flow velocity is about 1.5 m/s. Using wood chips as tracer particles, the flow field on the surface of the water inlet before and after packing is analyzed and studied through C language programming. In the basis of simulation analysis and structure optimization of water filler packing problem numerically, through the test of oxidation ditch experimental device, completed a water filler packing experiment, experimental results show that the actual project, pushing distance and water diving flow machine installation position should be less than 7.2 m, can change the position of diving pushing flow y offset machine installation to alleviate the problem of filler packing, oxidation ditch water without filler packing problem, need to maintain a pool of two low level difference, the difference of level should be kept below 0.72 M. Adding baffles can reduce the packing rate and alleviate the packing problem in different degrees. When the two tank level difference is 20 mm, adding the baffle can reduce the maximum packing rate of the packing from 16% to 3.6%. When the difference of the two pool level is 30 mm, the maximum packing rate of the packing can be reduced from 31% to 16.8% when adding the baffle. When the liquid level difference of the two tank is 40 mm, the maximum packing rate of the filler can be reduced from 35% to 18% by the addition of the baffle. (2) the CFD software is used to calculate the three dimensional numerical calculation of the oxidation ditch at the 1:36 size. The structure optimization of packing packing problem on the small scale oxidation ditch is used to guide the experimental research. It is found that the best parameter condition is: the position of n+20 5 mm, Z:+20 mm and baffle inclination angle are 7.5. The baffle counter clockwise 45. Open the hole. Add the counter clockwise 45. The opening angle of the opening is 7.5. The baffle can change the tangential velocity of the middle part from the counterflow speed of 0.05 m/s to the downstream speed of 0.1 m/s, and the maximum normal velocity in the upper and the middle parts is obviously reduced, which can alleviate the packing problem of the overflow port. (3) using CFD software to simulate the three-dimensional flow field of full-scale oxidation ditch, select some sections, analyze its hydraulic characteristics, and analyze the packing problem and energy allocation problem in the actual engineering. The key for the adjustment and optimization of energy configuration, design six kinds of working conditions, found in the corners, 1.5m export import 7.5 m at the distance of the curve is provided with a plug flow machine, installation position to the medial displacement of 0.25 m, to translate 0.25m, setting a single push flow machine power of 2.3 KW, 6 Taiwan, power configuration: 4.84 W/m3, the best effect.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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