Longitudinal diffusion by passing vehicles in road tunnels - investigation of experimental formula for longitudinal diffusion coefficient in road tunnels

摘要

A study was made on the use of longitudinal diffusion coefficients for predicting the concentration and emission of exhaust gas of vehivles in road tunnels. Study results have clarified the heretofore unclear effects by the direction of traffic or the number of lanes. Experimental equations have been established for calculating longitudinal diffusion coefficients. It was found that longitudinal diffusion coefficients could be established through the vehicular equivalent resistance area ratio alone, regardless of whether there was a one-way or two-way traffic in a tunnel. The knowledge attained has made it possible to estimate the longitudinal diffusion coefficient D for all types of vehicular road tunnels as well as for all traffic conditions. It is the wish of the authors that the attained knowledge be enthusiastically applied in the calculation of ventilation in road tunnels.