What is the role of tunnel fans in high-speed tunneling?

Tunnel fans are a product used in tunnel construction. In places where the air mobility is not good underground, external air supply is required, and a large amount of wind is required, and as the mining process increases, in addition to In addition to poor air circulation, some pollutants and dust in the air will also cause certain harm to the health of construction workers. At this time, 1-2 counter-rotating tunnel fans are placed outside the tunnel to deliver fresh air into the tunnel. While delivering fresh air, it can also extract harmful gases and dust from the tunnel, ensuring the construction environment and health of construction workers.

First of all, tunnels and underground railways are located tens of meters below the surface. The natural wind at the entrance and exit is very weak and must rely on some external forces. Then the tunnel fan is one of the products, used to transport and regulate air or Remove smoke and dust for the needs of staff and passengers.

Secondly, tunnel fans are generally hung on the top or sides of the tunnel, which does not occupy the traffic area, does not require the construction of additional air ducts, and has low civil construction costs; the fans are easy to install, operate and maintain, and are a very economical ventilation method. When the tunnel fan is running, part of the air in the tunnel is sucked in from one end of the fan, accelerated by the impeller, and ejected at high speed from the other end of the fan. This part of the high-speed airflow with higher kinetic energy transfers energy to other gases in the tunnel, generating a pressure rise that overcomes the tunnel resistance, thereby pushing the air in the tunnel to flow along the direction of the fan jet airflow. When the flow velocity decays to a certain level, the next group of fans continues to work. In this way, the purpose of sucking in fresh air from one end of the tunnel and exhausting dirty air from the other end is achieved.