Burning behavior and external flames in a corridor-like enclosure using liquid pool fires

This work presents an experimental study of the burning behaviors of ethanol pool fires in a corridor-like enclosure having an opening and a façade at one end. Three key parameters were examined, namely opening size, fire size and location of the fire. Tests were performed in a three-meter long corridor-like enclosure having a 0.5 m × 0.5 m cross section. In total, more than 60 experiments were conducted with eight opening sizes, two fire sizes and two fire locations. Measurements consist of mass loss rate, heat release rate, temperature inside the enclosure, heat flux on the floor as well as on the façade, gas and smoke production outside the enclosure and flame height using a CDD camera. Figure 1a plots the mass pyrolysis rate (ṁT) against the ventilation factor (AH1/2 where A and H are the area and height of the opening respectively), both normalized by the fuel surface area (AF). The trend of the present data follows that reported for a rectangular enclosure [1]. Specifically, in the ventilation-controlled region, the mass burning rate increases almost linearly with the ventilation factor, until it reaches its maximum corresponding to the transition from ventilation- to fuel-controlled conditions. With a further increase in the ventilation factor, the burning rate decreases until it reaches a constant value close to the one found in open burning conditions. Using the corridor-like enclosure, we found that at the ventilation-controlled stage the burning rate can be correlated with the ventilation factor by ṁT /AF =0.066 AH1/2/AF, as opposed to ṁT/AF=0.1AH1/2/AF for a rectangular enclosure. This may be explained by the fact that the temperature in the hot gas layer is not completely uniform as noted in the experimental data due to the large aspect ratio in the corridor-like configuration. The location and size of the fire also have a significant influence on the burning behaviors of the fire as shown in Fig. 1b, which compares the burning rate for cases with varying fire size and location. When the burner is located at the back, much higher burning rates were observed due to the increased radiation feedback from the hot gas layer and the enclosure’s walls and was also observed that the flame detaches from the burner, moves towards the opening and for certain cases emerges from the opening. Finally, we found that combustion efficiency decreases with a decrease in the opening size.