Empirical correlation derived by CFD simulation on heat source location and ventilation flow rate in a fire room

•Fire induced airflow in a room is numerically investigated for several heat source locations.•Vertical position of the heat source significantly affects the induced thermal flow and the ventilation rate.•Mathematical correlation linking the ventilation mass flow rate and the 3D fire source coordinates is established.•Good agreement is noticed when comparing the correlation results with experimental data.•Using this correlation, the ventilation flow rate is directly calculated in a fire case study regardless the heat source location. A series of numerical investigations of a fire induced airflow in a compartment are carried out using the Fluent 6.3CFD code, in order to examine the effect of the source location on the thermal flow field and the mass flow rate at the exit doorway. The Fire is modeled by a volumetric heat source and the induced transport flow phenomena is considered as a buoyancy-induced turbulent flow so Boussinesq approximations are applied. Resolution of the governing equations comprises the Reynolds averaged Navier-Stokes (RANS) equations using the k-ε turbulence model combined with an enhanced wall treatment. The research results show that the height position of the heat source has a significant impact on the temperature field and the stratification interface of the buoyant layer, comparing to the transversal or the longitudinal position. For the highest positions tested, the fire room becomes more stratified and essentially divided into two layers: an upper layer corresponding to the hot exhaust gases and a lower layer for the fresh air entrance. The second part of this paper was devoted to the establishment of a mathematical correlation linking firstly, the ventilation mass flow rate at the doorway exit, as a critical parameter in fire induced flow studies, and the three-dimensional coordinates of the fire source location within the room. The validity and accuracy of this mathematical correlation have been proven by comparing the results with available experimental data in the configuration studied and a good agreement was recorded.