الفهرس 
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Abstract
Tunnels are of increasing importance for the road network. The reason for this is the progression of the technology, the growing traffic and the awareness of maintaining urban and natural environment. Ventilation systems in road tunnels have an important role in providing tunnel patrons with a reasonable degree of comfort during normal operation and to assist in keeping tunnels safe during emergencies.
In this thesis, a study of air flow for ventilation of road tunnels is carried out. The study is intended to present the numerical solution of the governing equations for air flow in a road tunnel under a specific ventilation system. A finite volume method utilized by the commercial code ( FLUENT 6.2.16 ) is used to obtain the numerical solution. Distribution of air flow and dispersion of pollutants, as C02 and CO, inside the tunnel are studied. Different air parameters are studied like admitting air horizontal and vertical angles effect, portals sizes and portals spacing.
Effect of different traffic patterns including different car speeds on pollutants concentration, are studied in order to ensure a safe envirol1111ent inside the tunnel.
The results recommend ranges for horizontal and vertical admitting air angles. Portal spacing should not be increased to prevent formation of dead zones. To ensure certain air velocities, portal size must be well selected. Recommendation for amounts of admitted air in the tunnel according to speed of cars and spacing between them is presented.