Theoretical and experimental analysis of ceiling-jet flow in corridor fires

In tunnels or long corridors, the combustion products of the fire are confined to spread in one or two directions, forming a ceiling-jet flow. For safety assessment and emergency treatment, it is important to investigate and understand the behavior of the ceiling-jet flow. In this paper, a simple model has been presented, in terms of Richardson number and non-dimensional ceiling-jet thickness, to predict the temperature and the velocity of fire-induced ceiling-jet in a rectangular corridor. Besides, the location of hydraulic jump, occurring in ceiling-jet flow, has been estimated theoretically. In order to validate the theoretical predictions, a series of reduced-scale fire experiments were conducted in a 5 m long corridor. The predicted results, concerning non-dimensional excess temperature, agree favorably with experimental data in different fuels and heat release rates of the fire tests. Finally, the scaling issue has also been discussed and validated.

► A model of fire-induced ceiling-jet flow in a rectangular corridor has been developed.
► The model can predict the steady temperature and velocity along the corridor.
► The location of hydraulic jump, occurring in ceiling-jet flow, has been discussed.
► Twelve groups of fire tests were conducted to validate the model’s prediction.
► There is a good agreement between the experimental data and the model’s results.