The Influence of Diffuse Terminal Parameters on its Local Oxygen Performance in High-Altitude Railway Tunnels

Abstract

Oxygenation in the construction area is crucial for ensuring a safe working environment in high-altitude tunnels. At present, the main oxygen supply methods include personal respirators, full space oxygenation combined ventilation systems, and diffusion systems based on jet arrays; This paper uses a diffusion system based on jet arrays to conduct numerical simulations and studies the impact of terminal parameters on the local oxygenation performance of the tunnel face when the oxygenation amount is reduced from 4000m altitude to 3000m altitude. The relationship between terminal parameters, ventilation duct height, and oxygen concentration was fitted. The results show that the influence of each system terminal parameter on oxygen concentration presents a nonlinear relationship. And the oxygen concentration increases with the increase of pipe diameter, but the degree of increase decreases; However, there is little change in the spacing between pipes below 0.7m, while it is significant above 0.7m; The best effect is achieved when the distance from the wall is moderate; The inclination angle of the pipe has little effect; An increase in the height of the ventilation duct will increase the oxygen concentration and reduce the area of oxygen enrichment. This study has guiding significance for the design of supply schemes and oxygen environment control during the construction period of high-altitude tunnels.

Keywords: High altitude tunnel, Diffused oxygen supply, Oxygen supply terminal parameters, Computational fluid dynamics