Study On Thermal Environment Of Urban Street Canyon Based On Vehicle’s Impact

With the economical development and accelerated urbanization, the urban thermalenvironment is deteriorating. While vehicle exhaust heat is an important factor affectingthe urban thermal environment, most of which are mainly concentrated in urban streetcanyon. Through field measurement and numerical simulation, thermal environment of urbanstreet canyon based on vehicle’s impact was researched in this paper.(1) The thermal environment of Yuezhou Road which in Tianhe District of Guangzhou citywas measured, including the meteorological parameters, air temperature and humidity, windspeed, globe temperature at1.5m high as well as surface temperature of walls and vehicles inthe street canyon. What’s more, traffic flow in this area during this period was recorded. Thethermal environment characteristics of street canyon based on vehicle’s impact wasanalyzed. The results showed that there were obvious heat island phenomenon in YuezhouRoad area during the measured period and significant influence of vehicle on the thermalenvironment of the street canyon, for the reasons that: in addition to the vehicle exhaustheat, there were vehicle’s thermal radiation and disturbance caused by vehicle’s movement.(2) Based on the CFD software Fluent, the numerical simulation method for the thermalenvironment of urban street canyon considering the vehicle’s impact was established.Through thermal environment simulation of Yuezhou Road area during the measured period,and comparising with the experimental results, the rationality of the numerical simulationmethod was verified. The comparison of simulated and measured air temperature showedthat: Fluent can accurately simulate temporal and spatial distribution characteristics of the1.5m air temperature in the street canyon influenced by vehicle exhaust heat, which can beused in the numerical simulation analysis after.(3) Using the verified numerical simulation method, thermal environment of urban streetcanyon based on vehicle’s impact was researched. First of all, the standard street canyonmodel was established; and then on the basis of this, the influence of vehicle exhaust heaton the thermal environment of urban street canyon was analyzed; finally, from the aspect ofthermal environment, adaptive strategies of urban street canyon for vehicle’s impact wasdiscussed. The simulation results showed that: with the increase of vehicle exhaust heat, itsimpact on the1.5m air temperature rise of garage area weakened, while pedestrian areaincreased; The1.5m air temperature rising effect in urban street canyon which as a result ofvehicle exhaust heat increased with the decrease of street canyon aspect ratio, and with theincrease of street canyon length to height ratio. And the impact of length to height ratio is greater than the aspect ratio.