Study on the influence of ceiling tunnel angle on the gas shunting efficiency of urban highway tunnel

Abstract In order to analyse the feasibility of setting up a ceiling type purification and ventilation system in an urban highway tunnel and study the parameters of ceiling passage, this paper used Fluent software to carry out the 3D numerical simulation. The velocity and pressure distribution in the tunnel and the shunting efficiency were analysed under different angles between the ceiling passage and the main tunnel. Also, by comparing the velocity and CO concentration distribution in the tunnel, the purification efficiency under different conditions is verified. The results showed that the purification efficiency of a purified system is related to angles. With the increasing of angles, the shunting efficiency decreases. The equipment of the ceiling type purification and ventilation system in the urban highway tunnel can effectively reduce the CO concentration. The results show that it is feasible to install a ceiling type purification system as a new tunnel ventilation method, and it can provide a reference for future engineering design.