Influences of the train-wind and air-curtain to reduce the particle concentration inside a subway tunnel

• We investigate model subway tunnel numerically and experimentally to reduce particle concentration.
• We investigate influences of the air-curtain and train-wind on particle concentration.
• Mass flow rate passing through electric precipitator installed in Shaft 1 increases.
• Operating the air-curtain and train-wind reduces the particle concentration in the tunnel.

Subways are used widely for public transportation in major cities and require efficient ventilation systems to maintain indoor air quality in the subway tunnel. A subway tunnel was investigated numerically and experimentally to reduce the particle concentration in subway tunnels. The subway tunnel is 54-m long, 1.65-m high, and 2.5-m wide. The subway tunnel is one-quarter scale of a real subway tunnel. The tunnel has two U-type mechanical ventilation shafts. The steady three-dimensional airflow in the tunnel was analyzed using ANSYS CFX software to solve the Reynolds-averaged Navier–Stokes equations. The airflow in the tunnel and shafts was observed numerically using the train-wind and air-curtain. The effects of the train-wind, air-curtain, and electric precipitator were examined experimentally. The ventilation performance in the subway tunnel was observed with respect to the particle concentration in the tunnel. The numerical results suggest proper operating conditions for experimental analysis of the particle concentration. The average velocity of the airflow increases in the shaft when the velocity of the air-curtain increases. The particle concentration at the dust monitoring device after ventilation shaft 1 was reduced significantly in the tunnel when the air-curtain and train-wind were operated.