The difference between tunnel jet fan and tunnel axial fan is that the working principle is different. When the impeller rotates in the tunnel axial fan, the gas enters the impeller axially from the inlet, is pushed by the impeller blade and makes the energy of the gas rise, and then flows into the guide vane. The guide vane changes the deflected airflow into axial flow, and at the same time, the gas is introduced into the diffuser, which further converts the kinetic energy of the gas into pressure energy, and then into the working pipeline. Generally, the blades of axial flow fans can rotate at an Angle. Most axial flow fans are equipped with a set of blade hydraulic regulation devices. When the fan is running, the installation Angle of the blade can be adjusted through the blade hydraulic regulating device, and kept at a certain Angle, so that it still has a high efficiency in variable working conditions.

The tunnel jet fan is usually hung on the top of the tunnel or installed on the side wall of the tunnel, and the tunnel itself is used as the air duct. When the tunnel jet fan works, it can generate a higher thrust from the given energy. Part of the air in the tunnel is inhaled by the tunnel jet fan, and after work by the impeller, it is ejected out of the tunnel jet fan at high speed. Based on the principle of shock drive, the jet stream transfers energy to another part of the air in the tunnel, moving it backwards, pushing the air in the tunnel towards the exit and drawing in fresh air from the entrance. When the airflow velocity decays to a certain value, the next set of tunnel jet fans continue to drive the air flow in the same way, realizing the purpose of eliminating the polluted air in the tunnel.