Numerical Simulation of Haze-Fog Particle Dispersion in the Typical Urban Community by Using Discrete Phase Model

Hongbo Zhu,Jie Su,Dai Zhou,Yan Bao,Zhaolong Han,Xun Wang,Xuesen Wei

doi:10.3390/atmos11040381

Hongbo Zhu, Jie Su + Show 5 more

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https://doi.org/10.3390/atmos11040381

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Abstract

The haze-fog particle dispersion in urban communities will cause serious health and environmental problems, which has aroused society attention. The aim of the present investigation is to reveal the underlying mechanisms of haze-fog particle dispersion via Computational Fluid Dynamics (CFD) method, and then to provide a groundwork for the optimal spatial arrangement of urban architecture. The Delayed Detached-eddy Simulation turbulence model (DDES) and Discrete Phase Model (DPM) are utilized to investigate the wind flow distribution and the particle dispersion around the building group. The numerical results show that the particle dispersion is dominated by the incoming wind flow, the layout of architectural space and the type and distribution of vortex. The ‘single body’ wake pattern and the vortex impingement wake pattern are identified in the wind flow field, which have different effects on the distribution of haze-fog particle. The cavity formed by the layout of the building group induces primary vortex and secondary vortex, which will make it more difficult for the particles entering the square cavity to flow out. Moreover, the concentration of the particle in the rear of the buildings is relatively low due the effect of attached vortices.

Highlights

With the rapid development of urban construction, cities have attracted more people to work and live in them
The Computational Fluid Dynamics (CFD) simulations were validated by wind tunnel tests, and the results indicated that the Large-eddy Simulation (LES)
Referred to Zhu et al [38], it is named as vortex impingement type; (2) When the gap spacing between buildings is very small, the vortex shed from the front building will attach to the rear one, which is defined as ‘single body’

Summary

Introduction

With the rapid development of urban construction, cities have attracted more people to work and live in them. The air pollution seriously affects the health and life quality of inhabitants lived in cities [1]. According to the statistical data of World Health Organization (WHO), the air quality of about 97% of cities in low- and middle- income countries exceeds the limits of WHO air quality guidelines [2]. The fine particles in polluted air could lead to various diseases, including chronic respiratory diseases, heart disease, and even lung cancer. With the increasing concern to air quality, haze-fog has attracted more public attentions. Related with a high level of pollutant particles with different aerodynamic diameters, the mechanisms of the development and dispersion of haze-fog particle have not been fully understood

Methods

Results

Conclusion