Numerical Analysis of Ventilation System in Large Section Simulation Tunneling Roadway

In order to study the characteristics of dust removal by ventilation in large section tunneling roadway, experiments are carried out in a certain large section tunneling roadway under three different ventilation systems namely forcing, exhausting and mixed ventilation system. The velocity of observation point is obtained in the experiment. Then the wind flow field characteristics of the tunneling roadway with large cross-section under three different ventilation systems are analyzed. The software Fluent is used to simulate the experimental models. The results show that trend of simulated result is consistent with the trend of experimental result; and for tunneling roadway with large cross-section, exhausting system can hardly assure wind velocity near the working face in the required safe range; and compared with forcing system, there are few vortexes in tunnel under mixed ventilation system, and there is obvious air curtain, which means high dust removal efficiency; so mixed ventilation system is highly recommended to be used in tunneling roadway with large cross-section. Then numerical optimization is applied to the suggested mixed ventilation system. When the ratio of pressing air volume to absorption volume is about 1.2 and the height of forcing and exhausting pipe is about 2 m and 4 m respectively, the dust removal effect is better.