The self-extinguishing behavior of kerosene spray fire was investigated in a completely enclosed compartment with the size of 3 m × 3 m × 3.4 m.The spray was generated by locating one BETE nozzle at the center of the bottom wall.A series of spray fire videos were obtained by changing BETE nozzle type and injecting pressure.The results show that spray fire undergoes four stages: the growth stage,the quasi-steady stage,the stretch stage and the self-extinguishing stage.Consumption of large quantities of oxygen causes spray fire to first be stretched and then quench.In this process,fire base migrates away from spray region and leads to the emergence of ghosting fire.Ghosting fire promotes the instability of spray fire and large fluctuation of its height,which provides help to its self-extinguishing.With increasing the injecting pressure or the nozzle diameter,the self-extinguishing time decreases.It is found that the self-extinguishing time is approximately in inverse relation with injecting flow rate.Additionally,we also observed the occurrence of two-phase deflagration just after ignition,and it accelerates the spray fire growth and induces a larger fire height than the following quasi-steady spray fire.The deflagration turns stronger with increasing the injecting pressure.
The blended-fuel based eddy-dissipation-concept combustion model was newly developed in the FireFOAM framework, and applied to simulate30 cm×30 cm heptane-ethanol pool fire. Comparison was made of fire height,centerline temperature against experimental measurements, which shows that they match very well with each other. However, further studies are needed to examine the validation of this model in fire simulations with various scales.
Changjian WangJennifer WenYanming DingShouxiang Lu
