On the Metropolitan Expressway, large axial flow fans are installed in ventilation stations and jet fans are installed in tunnels to ensure the safety and comfort of passengers in tunnels, the working environment for maintenance workers, and to ensure an evacuation environment in the event of a fire and to ensure an atmospheric environment around the tunnel entrance and ventilation tower. Jet fans are installed suspended above the roadway inside the tunnel as shown in Figure 1, and inspection requires lane restrictions, which affect passenger traffic.
SHOJI et al. (Wed,) studied this question.