A Case Study of Thermal Environment in Urban Street Canyon in Hot and Humid Climate City based on Vehicle Effect

Abstract

Vehicle traffic is an important factor affecting the urban thermal environment, and most of them are mainly concentrated in urban street canyon. Through field measurement and numerical simulation, thermal environment of urban street canyon based on vehicle's impact was studied in this paper. The research works are as follows: 1) The numerical simulation method for the thermal environment of urban street canyon considering the vehicle' impact was established and verified by experimental results. Next, the impact of vehicles on the thermal environment in the urban street canyon was analysed. The simulation results showed that the air temperature in the street canyon increased gradually with the increase of vehicle exhaust heat. When vehicles heat generation rate increased 10W/m3, the 1.5m-height air temperature in the street canyon raised about 0.02 °C. With the increase of vehicle exhaust heat, its impact on the increase of air temperature in the garage area is weakened while that in the pedestrian area is improved. 2) The 1.5m-height air temperature rising effect in urban street canyon as a results of vehicle exhaust was found to be increased with the decrease of street canyon aspect ratio (height to width ratio) and the increase of length to height ratio. And the impact of length to height ratio is greater than that of aspect ratio. Then, the height to width and length to height ratios of street canyon should be designed in a reasonable range. And the reasonable distance from pedestrian area to road cars should be guaranteed to reduce the adverse effects of vehicle exhaust on pedestrian area.