水槽实验及数值模拟水体中污染物排放浓度场分布规律的研究

发布时间：2018-04-13 01:05

本文选题：水体中污染物排放 + 浓度场分布　；参考：《上海海洋大学》2015年硕士论文

【摘要】：研究污染物排放到环境水体中的扩散混合特征,在工程实践中,如污水排放管和扩散器的设计、排放水域和排放方式的选择、水质预测和水资源规划及保护等都具有十分重要的指导意义和实际价值。本文首先对目前国内外的浓度测量方法进行了归纳和分析,并确定利用定量的数字图像处理技术作为本文的浓度测量方法。然后采用物理实验与数值模型模拟相结合的方法,对水体中污染物排放浓度场的分布规律进行了研究。物理实验部分,重点建立了实验室里水体中污染物浓度的测量方法,此种方法较为科学准确,为实验室里水体中污染物浓度的测量提供了一种实用的方法。具体测量过程分为污染物浓度的标定和水槽实际测验两部分。在污染物浓度的标定实验中,分别在静水和动水两种状态下对污染物浓度进行了标定,并得到污染物浓度与图像灰度的关系曲线。对比两个关系曲线,分析发现污染物动水标定的实验过程在仪器布置等外界条件方面更接近实际水体中污染物排放时浓度场分布的水槽实验,所以选用动水标定的关系曲线作为计算浓度-灰度的对应关系曲线。在水槽测验中,采用不同来水流量和污染物排放流量进行了速度场和浓度场分布的测验,测验结果表明:(1)在一定的污染物排放流量的情况下,随着来水流量的增加,污染物排放口附近流速方向越来越接近X轴方向,且污染物的排放对环境流场的影响也越来越小;(2)在一定的来水流量的情况下,随着污染物排放流量的增加,污染物排放口附近流速方向越来越偏离X轴方向,且污染物排放口附近的流场变化越来越明显,即环境流体受到污染物排放的影响也越大。(3)在一定的污染物排放流量的情况下,随着来水流量的增加,浓度等值线逐渐向中间收缩,且扩散宽度越来越小,同时浓度轨迹线在排放管口附近逐渐向水槽左侧偏移;(4)在一定的来水流量的情况下,随着污染物排放流量的增加,浓度等值线逐渐向两侧扩张,且扩散宽度越来越大,同时浓度轨迹线逐渐向水槽右侧偏移。数值模拟部分,利用MIKE3软件对水体中污染物排放的速度场和浓度场分布进行了数值模拟,并用物理实验测量的水位数据、流速数据和浓度数据对数学模型进行了验证,验证结果较好。在此基础上,用数值模型模拟了不同工况下(与物理水槽实验工况相同)水体中污染物排放的浓度场分布,模拟结果表明:(1)在一定的污染物排放流量的情况下,随着来水流量的增加,区域内速度场发生了变化,具体表现为,整体流速不断增加,污染物排放口附近的流速减小区域越来越小,流速的方向越来越接近X轴方向,而速度场的变化导致了区域内的浓度场也发生了相应的变化,即浓度不对称区域逐渐减小,浓度等值线逐渐向中间收缩,且扩散宽度越来越小,同时浓度轨迹线在排放管口附近逐渐向水槽左侧偏移;(2)在一定的来水流量的情况下,随着污染物排放流量的增加,区域内速度场发生了变化,具体表现为,污染物排放口附近的流速减小区域越来越大,同时在污染物排放口附近流速的方向越来越偏离X轴方向,而速度场的变化导致了区域内的浓度场也发生了相应的变化,即浓度不对称区域逐渐增大,浓度等值线逐渐向两侧扩张,且扩散宽度越来越大,同时浓度轨迹线在排放管口附近逐渐向水槽右侧偏移。
[Abstract]:Study on pollutant emission to the diffusion mixing characteristics in environmental water, in engineering practice, such as sewage discharge pipe and the design of the diffuser, emissions and emission of waters, water quality prediction and water resources planning and protection are of great significance and practical value. This paper first analyzes and summarizes the concentration measurement methods at home and abroad, and determined by using digital image processing technique as a quantitative method for measuring concentration of this paper. Then the method combining simulation with physical experiment and numerical model of the distribution of the concentration field on the discharge of pollutants in water discharge were studied. Physical experiment, focusing on the establishment of the concentration of pollutants in the water measurement methods the laboratory, this method is more scientific and accurate, and provides a practical method for measuring the concentration of pollutants in water in the laboratory. The specific measurement The process is divided into two parts the pollutant concentration calibration and actual test. The tank calibration experiment of pollutant concentration, respectively in hydrostatic and hydrodynamic condition of two kinds of pollutant concentrations were calibrated, and get the relation curve of pollutant concentration and image. Comparing two curves analysis found that the experimental calibration process of water pollutants in the aspect of external conditions such as instrument layout is more close to the actual water pollutant emission concentration field distribution in flume experiments, so the selection of dynamic calibration curve of water as the corresponding curve of the calculated concentration gray. In the flume test, using different water flow and pollutant discharge flow of the velocity field and concentration field distribution test and the test results showed that: (1) in a certain traffic pollutant emission situation, with the increase of water flow and pollutant emission near the mouth of the flow direction more Come closer to the X axis, the environmental impact of the flow field and pollutant emissions are also increasingly small; (2) in the inflow of certain conditions, with the increase of pollutant discharge flow, pollutant emission near the mouth of the flow direction deviates from the direction of the X axis and the variation of the flow field near the mouth of the pollutant emission more and more obvious that is, the environment affected by fluid pollutant emissions increases. (3) in the traffic pollutant emission situation, with the increase of water flow, concentration contours gradually to the middle of contraction, and the diffusion width is more and more small, at the same time, concentration of track line emission in the pipe near the sink gradually to the left shift (4;) in the inflow of certain conditions, with the increase of pollutant emission flux, concentration contours to the sides gradually expanded, and the diffusion width increasing, while the concentration of track line gradually to the right side of the water tank. The numerical simulation of migration To be part of pollutant in the water velocity field and concentration field distribution was simulated by using MIKE3 software, and use level physical experimental data, verified the velocity data and the concentration data, verification results. On this basis, using the numerical model simulation under different conditions (with the same the physical condition of the concentration field of flume experiment) emissions of pollutants in the water, the simulation results show that: (1) in the traffic pollutant emission situation, with the increase of water flow in the region, the velocity field of the changes, specific performance, the overall flow rate increasing, emissions of pollutants near the mouth of the region and velocity decreases. The smaller the flow direction more and more close to the X axis, and the change of the velocity field caused the concentration field in the region has changed. The concentration of asymmetric regional concentration decreases gradually. Equivalent to the middle line gradually shrink, and the diffusion width is more and more small, at the same time, concentration of track line emission in the pipe near the sink gradually to the left shift; (2) water flow in certain circumstances, with the increase of pollutant discharge flow area, velocity changes, specific performance, emissions of pollutants near the mouth the velocity area is larger, while emissions near the mouth of the flow velocity in the direction of pollutants increasingly deviate from the direction of X axis, and the change of the velocity field caused the concentration field in the region has changed, namely asymmetric regional concentration gradually increased, concentration contours gradually to both sides of the expansion, and the diffusion width increasing at the same time, the concentration in the discharge orifice near the line gradually to the right side of the water tank offset.

【学位授予单位】：上海海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X52

【共引文献】