Study On The Dispersion Characteristics Of Airflow And Particle In Waterfront Residence Under Microclimate Environment

The urban water body which can adjust temperature and humidity of surrounding environment and buildings form the special microclimate environment.Surrounding areas of water body have strong commercial value because of its affinity and appreciation,so it attracts a number of developers to develop commercial and residential areas in the surrounding areas.With the increase of waterfront residences,vehicles and human activities also increase sharply,resulting in a large number of emissions of particulate matter,which seriously threatens the physical and mental health of residents in the community.The dispersion and distribution of particles are affected by many factors in waterfront residence,therefore,it is of great significance to study the transport mechanism of airflow and particle in waterfront residence under microclimate environment.This thesis takes the three-dimensional model of waterfront residence(water body is located on the west side of community)as research object,based on RNG k?? turbulence model,mixture model and discrete phase model,numerical model for the dispersion and transmission of water vapor and particle in waterfront residence is built,with fine particulate emitted by vehicle as pollution source and water vapor vaporized on water surface as source of changing atmospheric humidity.Taking a waterfront residence of Wuhan as an object,the wind speed,relative humidity,air temperature and particle mass concentration at different measuring points in waterfront residence are measured,and then compare the change trend of measured results with the numerical simulation.The results show that the measured results have the same trend with the numerical simulation results.The simulation results show that the mass fraction of water vapor increases with relative humidity,but its growth rate decreases.Without considering inter-particle condensation,particle mass concentration is positively proportional to relative humidity(?70%).When analyzing the dispersion and distribution of airflow and particle in waterfront residence under different dominant wind directions,it is found that wind environment in waterfront residence with the northeast is the best,with the best ventilation effect and the most favorable for rapid diffusion and elimination of particles.Ambient temperature affects the dispersion and distribution of airflow and particle in waterfront residence,particle mass concentration in waterfront residence of =27.5? is lower than that of =5.2?,the mass fraction of water vapor is higher than that of =5.2?,so environment quality and the residents' comfort of =27.5? in waterfront residence is better than that of =5.2?.Finally,based on the established numerical model,dispersion characteristics of water vapor and particle in waterfront residence with models of four different building arrangement(incremental,decreasing,concave and convex)are solved and analyzed.Results show that the dispersion range and content of water vapor in waterfront residence of incremental type are higher than the other three models.Besides,the dispersion range of particle in waterfront residence of descending type is the narrowest,with highest particle mass concentration around windward of the first column buildings,while particle dispersion range is the widest in concave type,and mass concentration of particle around windward of the first column buildings is relatively lower.