榆中县城大气污染物扩散的观测实验与数值模拟

结合榆中县外场观测实验资料,利用计算流体动力学CFD (Fluent)软件对榆中县城区的流场和污染物扩散形态及规律进行了模拟研究.根据实际测量数据,利用Gambit软件建立了榆中县城区的三维城市建筑模型,导入Fluent进行模拟计算,对模拟结果与观测数据进行了对比分析,结果显示Fluent对流场和污染物扩散的模拟具有较好的一致性;具体而言,对风向、风速的模拟值与观测值的总体相似系数分别为0.876和0.843,对0.5m和27m高度处污染物模拟值和观测值的相关系数分别为0.71和0.72.因此,Fluent软件可用于城市污染扩散的模拟研究,也可以根据其模拟结果指导空气质量检测点的布设.

Observational experiment and numerical simulation of air pollutant dispersion in Yuzhong

Based on the data from the field experiments in Yuzhong city of Gansu Province in China, flow field and tracer gas dispersion were simulated by using a CFD model Fluent. Firstly, a 3-dimensional urban building model was created by using the Gambit software according to the measured data, and then inputted into the Fluent model for computation. Comparison of the simulated wind and pollutant dispersion with the observed data showed that the simulated results were reasonable. The total similarity coefficient of wind direction and speed between simulated and observed data were 0.876 and 0.843, respectively, and the correlation coefficient of pollutant between simulated and observed data on the plane 0.5m and 27m above the ground level were 0.71 and 0.72, respectively. Therefore, the fluent model can be used for studying urban pollutant dispersion, and guiding the setup of air quality monitoring station based the simulated results.