CFD Prediction of Air Quality in the Area between Two City Road Tunnel Outlets Considering Moving Cars

conference paper

English

In the contribution, concentration field of different pollutants predicted with a CFD code will be presented. The calculations are done with StarCD code into which a special subroutine for moving vehicles is integrated. This subroutine is based on 3-D Eulerian-Lagrangian approach to moving objects and is capable of taking into account the traffic induced flow rate and turbulence (see Jicha et al., 2000). The method has a significant advantage of separating contributions from different sources to a total concentration field of different pollutants. In such a way we are able to clearly determine what is the impact of tunnel outlets, line sources from vehicles moving along roads and what is the background. The method has been applied to prediction of concentration field of CO and NOx in the city area located between two tunnel outlets - tunnel Strahov and tunnel Mrazovka in Prague. The modelled area has dimensions approximately 600m x 600m and is situated between two hills. Both tunnel outlets are connected with two-way road having 4 traffic lane in total and two ramps. Predictions were done for different traffic situations at both tunnel portals (traffic rate and speed) and different wind direction and speed. Also the "no-wind" conditions were modelled and one situation in which the ventilation system inside the tunnel Mrazovka is out of order which results in the highest amount of polluted air leaving the tunnel outlet into the adjacent area. Results show a very different area affected by emissions leaving the tunnel outlets and emissions from the road line sources under different conditions and can help local authorities to assess the interaction between tunnels and surrounding.

CFD Prediction, Air Quality, Road Tunnel

KATOLICKÝ, J., POSPÍŠIL, J., JÍCHA, M.

2001

1. 1. 2001

The Intitute of physics, Great Brirain

Loutraki, Greece

85–901939–3-4

The Third International Conference on Urban Air Quality

1135

1147

13