Temperature evolution, flame traveling transition structure inside a compartment of various fire source locations

The temperature evolution and flame traveling structure with fire growth from the fuel combustion of various source locations inside a compartment with a front opening at one end-side wall was explored in the present study. Concerning the compartment complex combustion (fire) dynamics, the temperature in a fire compartment based on the thermocouple array and the isotherm plane across the compartment center plane, flame appearance/structure obtained from the video camera and a critical heat release rate (HRR) for flame transition along the longitudinal direction of compartment were presented and discussed for a total of 329 experimental conditions. The flow dynamics conditions and combustion structures inside the compartment is presented to better interpret the experimental observation of the flame traveling/transition phenomenon. It is found that: (1) A flame traveling behavior was witnessed with increasing HRR, i.e., the flame first moves to the inner-side and then travels to the front-wall/opening of the compartment. This behavior is also reflected by the high temperature zone. (2) The temperature in a fire compartment first rises then varies little, eventually decreases with fire growth for all burner locations. Nevertheless, the temperature at the inner-side (closer to the backwall) decreases with the burner moving from the backwall to the front-wall/opening of the compartment. The temperature at the outer-side (closer to the front-wall/opening) changes little with HRR. A dimensionless correlation was raised according to the non-dimensional fire source location. (3) The flow field inside the compartment shows a significant difference for various burner locations. The flame traveling behavior from the inner-side to the outerside of the compartment is characterized by a critical HRR, which first increases then decreases with the burner moving from the backwall to the front-wall/opening, and increases with the opening ventilation factor. A non-dimensional correlation was proposed by two non-dimensional quantities of the critical HRR and the fire source location. These novel findings facilitate the understanding of fire dynamics concerning various fire source locations in a compartment with an opening.