Abstract
The aim of this investigation is to develop the central exhaustion systems which are clean ventilation system for road tunnels. In order to maintain environment around road tunnel portals, quantitative evaluation of exhaust gas emission from a road tunnel portal with central exhaustion system was numerically investigated. The sliding mesh with continuous moving technique is developed and utilized for ventilation analyses. The results of two-dimensional simulation show the gas emission rate depend on the location and flow rate of the central exhaustion. It revealed that the two-dimensional simulation gives us quantitative information. Three-dimensional attempts were also carried out. Three-dimensional simulation requires much computational time and resources. Then parametric survey is difficult with PC. However, three-dimensional simulations help us to understand the basic mechanism of gas emission at the tunnel portal. The present methods are therefore useful to understand the aerodynamics and environment for tunnel portals. The numerical simulation is one of the key technologies for the development of the clean system.
