Circular models of air distribution due to piston effect in subways

Subways as places of stay of many people are imposed with higher standards of microclimate at platforms and in tunnels, including the dust criterion. To reduce dust concentrations in tunnel air to MAC values, the authors suggest installation of filters at ventilation connections nearby platforms. Aimed to find operational parameters of the filtering facilities, the authors determine the air velocities at ventilation connections. An original approach is proposed to the air distribution analysis using circular models as they considerably diminish the subway test area size without the loss of the computational accuracy and reduce the computation time.