Numerical prediction of fugitive dust dispersion on reclaimed land in Korea.

摘要

The Saemangeum reclaimed land located on the western coast of Korea is one of the world's largest reclamation projects, developing 40,100 ha of land area. After construction of sea dikes in 2006, the exposed land area has been increasing in relation to the water level height. Dust from the exposed land, containing high amounts of salt, disperses to nearby areas. The dust is harmful to human and animal health as well as to plant growth. Therefore, an estimation of fugitive dust dispersion is necessary for the development of plans to manage the problem. Field experiments are ideal for understanding aerodynamic phenomena. However, finding a correlation between weather conditions and dust dispersion is a difficult task due to limited measuring points. Moreover, weather conditions are unstable, unpredictable, and cannot be artificially controlled. Field experiments also involve high labor and time expenses. To overcome these limitations, a computational fluid dynamics (CFD) model has been developed to analyze dust dispersion phenomena, both quantitatively and qualitatively, according to the topography of the area, under various weather conditions. Effort was devoted to improving the accuracy of the CFD model by taking into account topographical design, mesh structure, turbulence models, particle generation, and other factors influencing the final solution. Computed results of the 3-D developed CFD model were compared against experimental data. Results showed an average error of -6.8%, which is within the acceptable range. CFD-computed vertical log-profiles of dust dispersion were similar to the vertical profiles presented by an earlier study. CFD results showed that dispersion of fugitive dust was mainly affected by particle size, wind speed, wind direction, and topography of the area. The estimated dispersion distance, measured at a height of 3 m for the 10 micro m particles and a wind speed of 1.7 m s-1, was 3100 m. A dispersion distance of 6300 m was obtained when wind speed was 3.9 m s-1 for the 10 micro m particles. This study showed that a CFD model can be effectively used to supplement field experiments when analyzing dispersion of fugitive dust.