Longitudinal diffusion by passing vehicles in road tunnels (correlation equation on longituding diffusion coefficient and example of application)

摘要

This paper presents a correlation equation for estimating longitudinal diffusion coefficient of exhaust gas emitted by vehicles in road tunnels. The equation gives the coefficient for a given amount of traffic and passing Reynolds Number, expressed only by the equivalent resistance area of a vehicle. In addition, this paper shows an example of calculation for two-way traffic tunnel with natural ventilation, as well as the allowable length of tunnel with natural ventilation, concentration distribution and leakage ratio of pollutants at tunnel portals.