Experimental device for research on flow field and pollutant dispersion in urban continuous street canyons

Abstract

The invention discloses an experimental device for research on flow field and pollutant dispersion in urban continuous street canyons. The device comprises a wind tunnel mechanism, a continuous street canyon mechanism, a flue gas flow field tracer mechanism, a street canyon bottom plate heating mechanism, and a multi-parameter measurement mechanism. The continuous street canyon mechanism comprises two street canyons, three buildings and a bottom plate. The three buildings are formed by transparent fireproof glass, and the bottom plate is formed by firebricks. The street canyon bottom plate heating mechanism is made by arranging carbon-silicon heating rods in the bottom plate at equal intervals, and the heating rods heat the bottom plate evenly to simulate scenarios of the street canyon ground heated by different solar irradiation. The invention provides the experimental device for studying the flow field and typical pollutant dispersion rules in urban continuous street canyons under the coupled force of urban environmental wind and combustion strong heat buoyancy sources.

Description

technical field [0001] The invention relates to the field of pollutant diffusion in urban street canyons, in particular to an experimental device for researching flow field and pollutant diffusion in urban continuous canyon streets. Background technique [0002] With the rapid advancement of urbanization, urban high-rise buildings are gradually increasing. The space similar to the "street canyon" formed by adjacent high-rise buildings and the ground in the urban overlay layer is called the urban street canyon, or "street canyon" for short. Street canyons are the basic constituent units of cities. Affected by building height, density and volume ratio, street canyons formed by building groups with different height-to-width ratios have different shapes, which largely affect the flow field in street canyons; when the atmosphere When the incoming wind in the environment is perpendicular to the axis of the urban street canyon, a vortex will be formed inside the urban street canyo...

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Problems solved by technology

[0003] However, the current research on the flow field and pollutant diffusion characteristics in urban street canyons is mainly focused on the diffusion of motor vehicle exhaust, without considering the effect of strong thermal buoyancy sources. , the flow field structure and pollutant diffusion in the street canyon have behavior patterns and characteristics different from conventional athermal buoyancy sources and sunlight uniformly heating the ground

People do not have a deep understanding of the flow field display and the diffusion characteristics of typical pollutants in the case of burning strong thermal buoyancy sources such as fires in urban street canyons, especially for the continuous street canyon situation, the vortex generated by the external environmental wind The effect will draw pollutants into adjacent street canyons, which may lead to greater disasters

However, the existing on-site observation is affected by meteorological conditions, the boundary conditions are difficult to control, and accurate measurement cannot be achieved. At the same time, it is also restricted by the traffic environment. It is difficult to observe the flow field in the street valley with a large traffic flow.

It is impractical to conduct prior observations for buildings that are in the stage of architectural planning and design, and only some numerical calculations can be done. However, there are certain errors in the numerical simulation of the flow field and pollutant diffusion characteristics in large-scale street canyons, and the construction A large-scale experimental platform for the study of flow field and pollutant diffusion in street canyons is relatively costly and costly, and at the same time, it is difficult to accurately control the experimental boundary conditions. Therefore, it is urgent to establish a relevant physical experiment platform to carry out research on large-scale fires in scientifically designed urban street canyons. It has important reference significance for emergency response and decision-making of urban pollutant diffusion in the case of sudden accidents

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