A study on the smoke control characteristic of the longitudinally ventilated tunnel fire using PIV

A car accident involving the oil tank may result in continuously spreading spill fires in tunnels, which poses great threats to the entrapped cars. However, there is still no relevant work concerning this issue. This paper experimentally investigates the spill fires in a tunnel by means of a model-scale tunnel and a steel trench where the liquid fuel flows and burns. The findings show that in a quiescent environment, the burning area of the spill fires in the tunnel is notably smaller than that in open space, while the presence of wind influence the burning area significantly, largely depending on the wind speed. For all the tests, there is no obvious steady burning stage, instead a rebound in burning area is observed after a similar shrinking burning area as that in open space. Generally, the burning area initially increases and then decreases with the increasing wind speed. These findings provide a better understanding of spill fire behaviors in tunnels and can further offer guidance on the firefighting of such fires.