Simulation study of airflow-coal dust migration and diffusion law at entrance section of railway tunnel

In order to study the law of airflow migration and coal dust diffusion in the entrance section of railway tunnel, taking a railway tunnel as the research object, using Fluent software and based on dynamic mesh technology, the law of airflow field migration in the entrance section of tunnel is explored during the train entering the tunnel. The diffusion state of clouds with different coal dust particle sizes is analyzed, and the idea of dust suppression and the direction to be explored are put forward. The results show that the shape of the airflow at the entrance of the tunnel changes in a 'trumpet' shape. The influence range of the airflow on the X-Z and X-Y sections conforms to different forms of migration laws. The influence range of the vortex at the entrance of the tunnel is positively correlated with the position of the train. With the increase of coal dust particle size, the concentration area of coal dust cloud is closer to the ground. The closer the coal dust cloud is to the ground, the lower the coal dust concentration is. The research results are helpful to understand the law of airflow-coal dust migration and diffusion in the tunnel entrance section, and have guiding significance in reducing coal loss, inhibiting coal dust diffusion and protecting the life and health of railway workers.