Temperature distribution of fire-induced flow along tunnels under natural ventilation

A simple correlation is theoretically presented and numerically studied for the temperature distribution of fire-induced flow along tunnel ceiling, which could correlate the flow temperature for various tunnel aspect ratios and fire intensities. The aspect ratio of the tunnel cross section in the numerical models varies from 0.5 to 2.0, and the heat release rate of the fire source varies from 4.4 to 22 MW. The numerical results indicate that the correlation could be utilized for all tunnels but with separate fitting constants for aspect ratios less than unity and greater than or equal to unity, including all fire intensities considered. This correlation could prove valuable in fire modeling and installation design of fire detectors in tunnel-shape buildings.