An experimental device for research on the emission and diffusion of motor vehicle pollutants in urban street canyon roads

Abstract

The invention discloses an experimental facility for researching emission and diffusion of vehicle pollutants of urban street canyon roads. The experimental facility comprises an air stopping part, a street canyon building model and pollutant emission motor vehicle model part and a matching measurement and control part, wherein a wind field is provided by the air stopping part, and two building models on the upwind side and the downwind side constitute a street canyon road model; a motor vehicle model is arranged in the middle of a street canyon and is controlled to move by a wireless controller, and an engine and a tracer particle adding mechanism are connected through a hose on a vehicle; the motor vehicle model emits exhaust during moving in the street canyon and entrained with tracer particles; a digital camera is used for shooting moving images of the tracer particles illuminated by laser sheets; the concentration of the exhaust is measured through exhaust concentration measurement points arranged in the street canyon. The experimental facility greatly improves a previous experiment model, can more truly simulate the diffusion process of the pollutants emitted by the vehicles in the street canyon road environment, and has great significance on formulation of control and reduction methods of vehicle exhaust pollution.

Description

technical field [0001] The invention relates to the field of traffic pollutant discharge, in particular to an experimental simulation device for monitoring the flow and diffusion process of motor vehicle discharge pollutants in the street canyon road environment. Background technique [0002] In recent years, with the rapid development of the economy, the number of motor vehicles has continued to rise, and the urban air pollution problem caused by motor vehicle exhaust has become more and more serious. In addition, the urban street valley road environment is not conducive to the diffusion of pollutants, making motor vehicles The problem of exhaust pollution is more prominent, and has become a research hotspot in the field of transportation environment. The phenomenon of motor vehicle exhaust pollution on street valley roads affected by meteorological conditions and environmental wind fields is quite complicated. It is very difficult to arrange effective flow field measuremen...

AI Technical Summary

Problems solved by technology

The phenomenon of motor vehicle exhaust pollution on street valley roads affected by meteorological conditions and environmental wind fields is quite complicated. It is very difficult to arrange effective flow field measurement equipment in the actual street valley road environment. Therefore, the flow and diffusion of traffic pollutants in the actual road environment are very difficult. The process cannot be effectively measured, and probes can only be arranged at some points on the street to measure the change process of pollutants at that point over time, and it is impossible to grasp the overall movement process of traffic pollutants in street valley roads

In recent years, with the development of numerical simulation theory and computer technology, Chang et al. have established some models through the CFD numerical simulation platform to conduct research on the flow and diffusion of motor vehicle pollutants in street valleys. The support of the experimental results

Scholars such as Meroney used wind tunnels to carry out experimental research on the diffusion of traffic pollutants in street canyons, but they used ethane-air mixture as the simulated pollution source, which is quite different from the actual pollution source, and they did not consider the heating of street pavement and walls by sunlight The thermal buoyancy effect formed later, and the layout is relatively fixed, only the case where the wind field is perpendicular to the street valley road is studied, and the angle of the wind field is not considered

In addition, Liu Zhihui et al. used salt water experiments to simulate the flow field characteristics of air flow when there is ground heating in street valleys, but did not study the diffusion characteristics of pollutants

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