(1) The fan is reversible.

Compared with the one-way fan, the reverse fan has lower frequency and higher noise, but this fan can make the tunnel operation more selective. If there are special needs, a one-way channel can be used to make two channels run. When the fire is burning, the fan can exhaust smoke in reverse.

(2) Interval

In the wind tunnel, if there is a residual distance between each fan unit, the wind jet will gradually accelerate, and if the cyclone acceleration is insufficient, it will reflect the working performance of the downwind. The arrangement of the falling fans in the wind tunnel does not have to be equal. If there is a remaining longitudinal distance between the fans, the fans can be arranged near the tunnel entrance as much as possible; if the axial installation position of the fans is guaranteed to have a certain offset, the longitudinal distance between the fans can be reduced to return the installation coefficient. What is the thrust of the boring machine?

3) The flow rate of the tunnel fan.

If the atmosphere at the outlet of the fan is in an active state, the change value of the air momentum in the fan must decrease. The thrust of the fan is determined according to the change of the fan's atmospheric momentum in the moving atmosphere. If the installation position of the falling blower is close to the tunnel wall or vault, the external force collision between the downward airflow and the vault wall or vault disappears.

(4) Size

The ratio of reduced power to thrust is related to the wind speed of the fan inlet. In the case of meeting the thrust requirements, the larger the air inlet, the greater the power consumption. When the size of the fan is constant, the increase in thrust will inevitably increase the size of the fan unit, thereby increasing the investment in the fan itself. However, at this time, the wind speed at the fan inlet will also increase, so that the quencher cannot be used and the length is reduced. In order to improve the operation interest, the fan with large diameter, low speed and small blade position should be selected as much as possible.