Numerical simulation of flow field characteristics and pollutant transport under different ventilation modes

A large amount of pollutants are generated during tunnel blasting construction, which seriously endangers the life and health of construction personnel. Reasonable design and resolution of ventilation issues have become the key to ensure the safety of engineering construction. This study established a ventilation simulation engineering during tunnel construction using numerical methods of computational fluid dynamics. The mechanism of the turbulent air flow generated by the restriction of air jet and wall is proved by simulating the distribution of the flow field in the tunnel under various ventilation modes. The retarding effect of vortex conducted by air flow and pollutant transport diffusion mechanism resulted in two peak distributions of pollutants. The discharge of harmful gases has both the transport effect of the main airflow and the diffusion effect of the turbulent airflow. Jet fans can effectively accelerate the dispersion of pollutants in the vortex zone. The time cost law of ventilation saving under different ventilation modes is found through comparison. On this basis, a new annular ventilation method combining longitudinal and transverse ventilation in tunnels is proposed. Not only can it greatly save ventilation time and costs, but it also provides a very friendly solution to the residual pollutants in the vicinity of the working face. The research work of this project provides important reference and guidance value for practical engineering. The distribution law of air flow field and the mechanism of pollutant transport and diffusion in the tunnel are revealed.A new type of ventilation mode is constructed based on numerical simulation.The advantages and disadvantages of different ventilation modes are analyzed and compared to provide guidance for practical projects.