RESEARCH ON POLLUTANT DISPERSION OF CO AND NOX BASED ON INVERSE PROBLEM METHOD WITH SOURCE ITEM IN MULTI-RAMPS URBAN TUNNEL

摘要

Compared with the straight tunnel, pollutants emission, migration and accumulation in themain tunnel is affect by the complex tunnel structures, and ultimately the pollutantsconcentration distribution in the entire tunnel is complicated. Results in a research gap onmulti-ramps urban tunnel ventilation engineering design. The aim of this study was to showthe dynamic diffusion characteristics influenced by ramps. The pollutant source itemaccumulated values from vehicle emissions and multi-ramps pollutants were obtained withmass transfer equation through the inverse problem method, which based on themeasurement results. Results show that the average back calculated CO and NO_x sourceaccumulated values were 0.37mg/m~3s and 0.044mg/m~3s, respectively. In congestionconditions of workday morning peak hours, pollutants into main tunnel from confluenceramp made a slight increase of 4.8% of total pollutants source, and flowed into diversionramp from main tunnel was 5.2%. The result can provide a quantitative assessmentmethod to support pollutant concentration control and contribution of the required airvolume by traffic flow in multi-ramps urban tunnel.