• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>Tenth International Conference on Modelling, Monitoring and Management of Air Pollution Jul, 2002 City of Segovia >Wind tunnel study on the pollutant dispersion over an urban area
【24h】

Wind tunnel study on the pollutant dispersion over an urban area

机译：风洞研究城市污染物扩散

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

This paper presents a wind tunnel study of the pollutant dispersion over an urban area with three different types of thermal stability within the atmospheric boundary layer. The diffusion fields in the boundary layer were examined in three flow obstacle cases: ⅰ) boundary layer without flow obstacles, ⅱ) boundary layer over two-dimensional fence, and ⅲ) boundary layer over three-dimensional cubic building model. The scale of the model experiment is assumed to be at 1:500. In the experiment, gaseous pollutant is discharged in the simulated boundary layer over the flat terrain. Ethylene, C_2H_4, is used as tracer gas and a hydrocarbon analyzer detector (FID) is used to measure its concentration. The effluent velocity of the pollutant is set to be negligible. The density of pollutant gas is the same at the height of the pollutant effluent in the boundary layer. These experiments are performed in the stratified wind tunnel under three atmospheric conditions: stable (Ri_B=0.118), neutral (Ri_B=0.0) and unstable (Ri_B=-0.096). Wind velocity profile of 1/4 power law is simulated for all three cases. Concentration distributions (vertical and horizontal) were measured at four positions in the leeward direction (2, 3 , 6 and 13 H_m from gas source, where H_m is obstacle height). Laser Doppler Velocimetry (LDV) is used to measure the velocity field and the turbulence characteristics are analyzed. The results obtained are as the following: a) a thick internal boundary layer is generated in the case with 2D fence, b) the inner boundary layer is very thick around the wake region due to the turbulence mixing, c) the reattachment length of the separated flows with the 2D fence is longer than that with the cubic model, d) the vertical and horizontal distributions of concentration with the 2D fence are smaller than that with the cubic model. The concentration distributions measured in the experiment may be used for the evaluation of numerical models and expert estimating of air quality in the urban environment.
机译：本文提出了一种风洞研究方法，研究了大气边界层内三种不同类型热稳定性的城市区域污染物扩散。在三种流动障碍情况下检查了边界层中的扩散场：ⅰ）没有流动障碍的边界层，ⅱ）二维栅栏上的边界层，ⅲ）三维立方模型上的边界层。假设模型实验的比例为1：500。在实验中，气态污染物在平坦地形上的模拟边界层中排放。乙烯C_2H_4用作示踪气体，碳氢化合物分析仪（FID）用于测量其浓度。污染物的流出速度设置为可忽略不计。在边界层的污染物排放高度处，污染物气体的密度相同。这些实验是在分层风洞中的三种大气条件下进行的：稳定（Ri_B = 0.118），中性（Ri_B = 0.0）和不稳定（Ri_B = -0.096）。对所有三种情况都模拟了1/4幂律的风速分布。在背风方向的四个位置（距气源的H，m为2、3、6和13 H_m，其中H_m为障碍物高度）测量了浓度分布（垂直和水平）。激光多普勒测速仪（LDV）用于测量速度场并分析湍流特性。得到的结果如下：a）在使用2D栅栏的情况下，生成了一个厚的内部边界层，b）由于湍流混合，在尾流区域周围的内部边界层非常厚，c）网格的重新附着长度二维栅栏的分离流比立方模型的流长，d）二维栅栏的浓度的垂直和水平分布小于立方模型。实验中测得的浓度分布可用于评估数值模型和专家评估城市环境中的空气质量。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号