Large Eddy Simulation of wind flow impact on fire-induced indoor and outdoor air pollution in an idealized street canyon

Pešić, Dušica; Zigar, Darko; Anghel, Ion; Glisovic, Srdjan

doi:10.1016/j.jweia.2016.05.005

Cited by 38 publications

(9 citation statements)

References 41 publications

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“…The important concept of “critical recirculation velocity” was initially proposed by Hu [ 20 ]; namely, when the cross-wind velocity is greater than this critical level, fire smoke will be recirculated back inside the canyon, imposing much more serious fire and smoke hazards for evacuation and emergency rescue. The critical recirculation velocity for different fire locations and heat release rates was further obtained by Hu [ 20 , 21 ], Pesic [ 22 , 23 , 24 ] and Wang [ 25 ], and then a dimensionless factor called the Froude number (denoted as Fr) was introduced to reflect the competition of inertia force (due to ambient wind) versus thermal buoyancy (due to fire). Zhang [ 26 ] studied an urban street canyon formed by wedge roof buildings and found that the flow pattern of pollutant plume dispersion inside the street canyon with increasing wind speed for different roof inclination angles could be divided into three regimes.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Smoke Recirculation Behavior in Street Canyons with Different Aspect Ratios and Cross-Wind Conditions

Xiang

Wang

et al. 2022

IJERPH

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This study investigated smoke dispersion inside a street canyon in a series of numerical simulations. The building height and street width as well as the cross-wind velocity were changed during the simulation, and the smoke recirculation behavior inside the canyon is presented and discussed. The results show that the smoke recirculation behavior could be distinguished into two different stages, i.e., the “fully recirculation stage” and “semi recirculation stage”, which is strongly determined by the canyon aspect ratio (the building height divided by street width). It was found that the critical wind velocity at which the smoke recirculation would take place was almost constant for an ideal street canyon with an aspect ratio of 1; however, this velocity was decreased with increasing building height or decreasing street width, indicating a much more dangerous circumstance when the aspect ratio is greater. Finally, a new piecewise function is proposed for the critical smoke recirculation velocity for all cases, which can provide some theoretical basis for building designs and emergency rescue for human beings inside the street canyon.

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Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Smoke Recirculation Behavior in Street Canyons with Different Aspect Ratios and Cross-Wind Conditions

Xiang

Wang

et al. 2022

IJERPH

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“…As a consequence, dense and tall buildings are sometimes responsible both for increased levels of harmful substances in the air (especially in city centers) and for strong local air turbulence. There are also complex phenomena described by the theory of aerodynamics [23,24]. Models of pollution flow and spread in urban areas [25] have been created to reflect real phenomena and present information on how building affect the accumulation of pollutants.…”

Section: Introductionmentioning

confidence: 99%

3D Spatial Analysis of Particulate Matter (PM10, PM2.5 and PM1.0) and Gaseous Pollutants (H2S, SO2 and VOC) in Urban Areas Surrounding a Large Heat and Power Plant

Cichowicz

Dobrzański

2021

Energies

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In many regions of the world, the winter period is a time of poor air quality, due primarily to the increased use of individual and district heating systems. As a consequence, the atmospheric air contains increased concentrations of both particulate matter and gaseous pollutants (as a result of “low” emissions at altitudes of up to 40 m and “high” emissions more than 40 m above ground level). In winter, the increased pollution is very often exacerbated by meteorological conditions, including air temperature, pressure, air speed, wind direction, and thermal inversion. Here, we analyze the concentrations of particulate matter (PM10, PM2.5, and PM1.0) and gaseous pollutants (H2S, SO2, and VOC) in the immediate vicinity of a large solid fuel-fired heat and power plant located in an urban agglomeration. Two locations were selected for analysis. The first was close to an air quality measurement station in the center of a multi-family housing estate. The second was the intersection of two main communication routes. To determine the impact of “low” and “high” emissions on air quality, the selected pollutants were measured at heights of between 2 and 50 m using an unmanned aerial vehicle. The results were compared with permissible standards for the concentration of pollutants. Temperature inversion was found to have a strong influence on the level of pollutants at various heights, with higher concentrations of particulate matter registered at altitudes above 40 m. The source of PM, H2S, and SO2 pollutants was confirmed to be “low emission” from local transport, industrial plant areas, and the housing estate comprising detached houses located in the vicinity of the measuring points. “High emission” was found to be responsible for the high concentrations of VOC at altitudes of more than 40 m above the intersection and in the area of the housing estate.

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“…These can cause zones of increased wind speed, turbulence, or air stagnation. Pollutants may accumulate in zones of air turbulence and stagnation [18] Research on the flow and spread of pollution in urban settings using models has a number of advantages [17]. Based on such analyses, the movement of pollutants in cities was linked to so-called street canyons, i.e., city streets surrounded by relatively tall buildings.…”

Section: Introductionmentioning

confidence: 99%

Spatial Analysis (Measurements at Heights of 10 m and 20 m above Ground Level) of the Concentrations of Particulate Matter (PM10, PM2.5, and PM1.0) and Gaseous Pollutants (H2S) on the University Campus: A Case Study

Cichowicz

Dobrzański

2021

Atmosphere

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Spatial analysis of the distribution of particulate matter PM10, PM2.5, PM1.0, and hydrogen sulfide (H2S) gas pollution was performed in the area around a university library building. The reasons for the subject matter were reports related to the perceptible odor characteristic of hydrogen sulfide and a general poor assessment of air quality by employees and students. Due to the area of analysis, it was decided to perform measurements at two heights, 10 m and 20 m above ground level, using measuring equipment attached to a DJI Matrice 600 unmanned aerial vehicle (UAV). The aim of the measurements was air quality assessment and investigate the convergence of the theory of air flow around the building with the spatial distribution of air pollutants. Considerable differences of up to 63% were observed in the concentrations of pollutants measured around the building, especially between opposite sides, depending on the direction of the wind. To explain these differences, the theory of aerodynamics was applied to visualize the probable airflow in the direction of the wind. A strong convergence was observed between the aerodynamic model and the spatial distribution of pollutants. This was evidenced by the high concentrations of dust in the areas of strong turbulence at the edges of the building and on the leeward side. The accumulation of pollutants was also clearly noticeable in these locations. A high concentration of H2S was recorded around the library building on the side of the car park. On the other hand, the air turbulence around the building dispersed the gas pollution, causing the concentration of H2S to drop on the leeward side. It was confirmed that in some analyzed areas the permissible concentration of H2S was exceeded.

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Large Eddy Simulation of wind flow impact on fire-induced indoor and outdoor air pollution in an idealized street canyon

Cited by 38 publications

References 41 publications

Numerical Simulation of the Smoke Recirculation Behavior in Street Canyons with Different Aspect Ratios and Cross-Wind Conditions

Numerical Simulation of the Smoke Recirculation Behavior in Street Canyons with Different Aspect Ratios and Cross-Wind Conditions

3D Spatial Analysis of Particulate Matter (PM10, PM2.5 and PM1.0) and Gaseous Pollutants (H2S, SO2 and VOC) in Urban Areas Surrounding a Large Heat and Power Plant

Spatial Analysis (Measurements at Heights of 10 m and 20 m above Ground Level) of the Concentrations of Particulate Matter (PM10, PM2.5, and PM1.0) and Gaseous Pollutants (H2S) on the University Campus: A Case Study

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