Study on ventilation simulation of underground energy storage tunnel construction in extreme cold region

Abstract

Based on a large underground storage tunnel project in a extreme cold area, the numerical simulation of pollutants and temperature field during tunnel excavation is carried out. The three-dimensional numerical model of long tunnel excavated is established, and the three-dimensional flow field and temperature field are simulated by CFD method, and the rationality of the numerical simulation is verified. Accordingly, the wind field and CO migration and distribution rule in the tunnel under different ventilation modes are further simulated, and the influence rule of mechanical ventilation on the temperature field of the tunnel is analyzed. The simulation result show that the pollutant field near the working surface and the influence of external cold air migration should be considered at the same time in tunnel excavation in extreme cold regions. The compressed ventilation has a long discharge path and a longer time for pollutant concentration to reach the standard, and the smoke exhaust window takes a longer time for pollutant concentration to reach the standard. However, the main roadway is not affected by the cold air outside the tunnel, and the loose smoke at the entrance of the main alley will have a stable cooling and heat convection exchange area at the entrance of the roadway.The pollutants can be effectively discharged by using mixed ventilation, however, the negative pressure generated by the extraction fan will accelerate the injection of cold air outside the tunnel. Attention should be paid to the balance of the pumping air volume and the insulation of the entrance, so as to reduce the influence of cold air on the temperature field of the tunnel.

Keywords

extreme cold regions / long tunnel excavated / CFD simulation / compressed ventilation / mixed ventilation / CO concentration field / temperature field