污水管道有害性气体运动与分布规律研究

发布时间：2018-10-08 13:47

【摘要】：随着城市规模的逐渐发展扩大,城市污水管道的运行安全逐渐成为需要重点关注的领域。本文针对污水管道内气体的运动和有害性气体的分布规律展开了相关研究。利用CFD模拟技术对污水管道通风数学模型进行了验证,以验证其准确性;利用VOF模型对污水管道检查井跌水进行了模拟计算,得到了不同开孔状态下的等效通风机特性曲线,并将其与管道阻力曲线联立,确定一段特定管段通风量;利用微元法对污水管道内有害性气体的运动与分布规律进行了建模,得到了三种气体分布的典型状态,主要研究结论有:(1)利用CFD验证可知利用数学模型对污水管网进行有害性气体通风计算是可行的,离跌水井越近的检查井小孔空气流率越大,(2)跌水井井盖开孔一般为吸气,即新鲜空气会通过跌水处的井盖开启孔进入污水管道,越远离跌水的检查井小孔空气流量越小(3)通过与竖桶试验结果对比,利用VOF算法模拟结果与试验结果平均误差为7.43%,最大误差为12.5%,因此可以认为利用VOF算法计算污水管道跌水进风量是可行的。(4)DN800的污水管道,在开孔比分别为0.125%、0.5%、1%和100%时,污水管道安全通风长度分别为246m、626m、705m和741m。适当增加开孔比可以显著增加有效通风长度。而开启孔大到一定程度时,继续增加开孔效果不显著。当跌水井后方管道长度大于安全长度时,甲烷有达到爆炸极限的风险,为保证管道安全运行,应考虑安装辅助通风装置。(5)通过对污水管道有害性气体的运动与分布规律进行建模分析,可以得到3种典型的污水管道中有害性气体分布状态。分别是逐渐减小;逐渐增大;先增大后减小。
[Abstract]:With the development of urban scale, the safety of urban sewerage pipeline has gradually become the focus of attention. In this paper, the movement of gases and the distribution of harmful gases in sewage pipes are studied. The mathematical model of sewer duct ventilation is verified by CFD simulation technology, and the VOF model is used to simulate the water drop of sewage pipeline inspection well, and the characteristic curve of equivalent ventilator is obtained under different opening conditions. At the same time, it is combined with the pipeline resistance curve to determine the ventilation volume of a particular section of the pipe, and the movement and distribution of the hazardous gas in the sewage pipe are modeled by using the micro-element method, and the typical states of the three kinds of gas distribution are obtained. The main conclusions are as follows: (1) using CFD to verify that it is feasible to calculate harmful gas ventilation in sewage pipe network by using mathematical model, the smaller the air flow rate is in the inspection well near the falling well, and (2) the air flow rate in the hole in the cap of falling well is generally suction. That is, fresh air will enter the sewer pipe through the hole opening in the well cover where the water falls. The farther away from the falling water, the smaller the air flow rate in the inspection well is (3) compared with the results of the vertical barrel test. The average error between the simulation result of VOF algorithm and the test result is 7.43 and the maximum error is 12.5. Therefore, it can be considered that it is feasible to use VOF algorithm to calculate the air volume of the sewer pipe. (4) the sewer pipe with DN800 has an opening ratio of 0.125% and 0.5% and 100% respectively. The safe ventilation length of sewer pipe is 246m / 626mt 705m and 741mrespectively. The effective ventilation length can be significantly increased by increasing the opening ratio. However, when the opening hole is large enough to a certain extent, the effect of increasing the opening hole is not significant. When the length of the pipe behind the falling well is greater than the safe length, methane is at risk of reaching the explosion limit, so as to ensure the safe operation of the pipeline, (5) through modeling and analyzing the movement and distribution of harmful gases in sewer pipes, three typical distribution states of harmful gases in sewer pipes can be obtained. They are gradually decreasing; gradually increasing; first increasing and then decreasing.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU992.23

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