An experimental model for research on the diffusion and distribution of nitrogen oxides in street-canyon road intersections

Abstract

The invention discloses a street canyon type road intersection inner nitrogen oxide diffusion and distribution research experiment model, comprising a wind wall system, a city street canyon intersection model, a linear discharge source model, a PIV tracing system, and a nitrogen oxide detection system, wherein the wind wall system provides a wind filed for experiments; the city street canyon intersection model is composed of a cross intersection enclosed by four building models; linear nitrogen oxide discharge sources are distributed on streets, and are in connection through a flexible pipe, a nitrogen oxide generation device and a tracing particle adder; a street canyon intersection releases nitrogen oxides mixed with tracing particles, a nitrogen oxide detector arranged at the street canyon intersection detects the concentration in the street canyon intersection, and meanwhile a digital camera records the diffusion images of tracking particles illuminated by a laser light source. The model can simulate the diffusion of nitrogen oxides discharged by street canyon type road intersection motor vehicles, and is of great significance in making a scheme of reducing street canyon type road intersection nitrogen oxide pollutants.

Description

technical field [0001] The invention relates to the field of traffic pollutant discharge, in particular to an experimental model for researching the diffusion and distribution of nitrogen oxides in street-canyon road intersections. Background technique [0002] In recent years, with the rapid urbanization, the number of urban motor vehicles has continued to increase, resulting in the exhaust gas emitted by motor vehicles gradually becoming one of the main sources of urban air pollutants. Like industrial waste gas, the nitrogen oxides emitted by motor vehicles are also affected by factors such as weather, terrain, and building shapes, especially the obstruction of the airflow by the buildings on both sides of the road, which seriously weakens the transport of nitrogen oxides in the exhaust gas. and diffusion, causing the nitrogen oxide content in the vicinity of urban street valleys to seriously exceed the standard, especially at the intersection of street valley roads, where...

AI Technical Summary

Problems solved by technology

Based on the current technical conditions, it is very difficult to arrange effective flow field measuring instruments in the actual urban intersection environment. Only a small number of measuring points can be arranged. The measured pollutants change with time, and the overall diffusion of pollutants at the intersection cannot be determined. Behavior, and there are too many accidental factors at street canyon road intersections in the actual city, which is not conducive to the control of the experiment

With the continuous development of computer technology, the CFD method has become one of the important ways to numerically simulate the diffusion behavior of pollutants under complex building conditions. Although scholars at home and abroad have achieved certain results through numerical simulation methods, they lack the support of experimental results. Therefore, Constructing a small-scale experimental model that is close to reality is an important choice for studying the dispersion of motor vehicle pollutants at urban street canyon road intersections, and it has a reference role in formulating effective methods for improving the air environment at intersections

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