垃圾焚烧烟气扩散的多尺度模拟与分析

Multiscale Simulation and Analysis on the Diffusion of the Waste Incineration Flue Gas

垃圾焚烧会产生大量的二次污染,使得原本极为推崇的垃圾焚烧发电倍受质疑。本文利用CFD技术对垃圾焚烧产生的烟气通过烟囱高空扩散的规律进行数值模拟,研究在多尺度空间条件下流场和污染物分布。采用标准κ-ε湍流模型及组分输运模型,分析不同排烟高度和速度对排烟地点下风向1.4 km小区建筑群内污染物分布的影响。研究表明SO_2、二恶英等烟气污染物在小区建筑间的浓度分布随着排烟高度和速度的增加而减弱,但由于气流分布产生涡旋的影响使得建筑物背风面污染物浓度较高。本文将计算结果与正态分布假设下的高斯烟羽模型计算结果进行比较,两者有较好的一致性。

The large number of secondary pollutants,which were produced from waste incineration flue gas,would cause the highly admired waste incineration power generating project into questions.The CFD technology was applied to simulate the diffusion characteristics of waste incineration flue gas from chimney,to investigate the flow and pollutant distribution at multiscale space conditions.The standard k- ε turbulence model and component transport model were adopted to evaluate the pollutant distribution influence between buildings at downwind 1.4 km from discharge position with different exhaust height and velocity.It was found that the concentration distribution of flue gas pollutant,such as SO_2 and TCDD,decreased with the increase of exhaust height and velocity,and a higher pollutant concentration on the leeward of buildings was caused by the vortex induced from wind field.Finally,the analysis results of Gaussian plume model were found to be in a good agreement with the simulation results.