# A Review of Modelling and Simulation Methods for Flashover Prediction in Confined Space Fires
## 2 Modelling and Simulation of Flashover Phenomenon
### Flashover Simulation
In one of them [28], two independent datasets ([PERSON] numerical results and [PERSON] experimental measurements) were used to successfully validate Fire 3D (CFD model), quantitative predictions about velocity and temperature fields in enclosure fires. Furthermore, a comparison among [PERSON]'s experimental data [24] (which had been extensively used as a benchmark to validate various mathematical/computer fire models) and two other types of CFD software data simulations(ANSYS CFX-5 and FDS) were made to test ANSYS CFX-5 by [PERSON] et al. [41]. Some aspects of the simulations were compared and ANSYS CFX-5 CFD tool results agreed reasonably well with the measured fire data. The fire model provided reasonable predictions of the thermal flow fields under fully ventilated conditions. The time spent by ANSYS CFX-5 during the process was shorter compared to FDS. It was concluded that the understanding of the fire dynamics and advances made in numerical methods and computer hardware would have a significant impact on the performance of CFD fire models in the future. In addition, numerical simulations were carried out by [PERSON] et al. [42] to investigate the accuracy of fire dynamics simulator (FDS) in poorly ventilated fires with external flame. This study demonstrated the accuracy obtained with FDS software [43] to calculate and reproduce this kind of phenomenon. The results were validated with two methods, one of them based on temperature and the other one based on the volumetric heat release velocity. To carry out this study 32 simulations were accomplished for different opening geometries: 0.1 m \(\times\) 0.2 m; 0.2 m \(\times\) 0.2 m; 0.2 m \(\times\) 0.3 m; and, 0.3 m \(\times\) 0.3 m. The accuracy of the results obtained was discussed, comparing experimental data with empirical correlations. FDS proved to be capable of reproducing the neutral plane height for the various configurations with high degree of accuracy. Nevertheless, authors noticed some uncertainty at the level of the experimental data, since the HRR inside the enclosure could not be measured directly. Several studies have carried out simulations of flashover with CFD techniques. As can be consulted in the previous paragraph, FDS has proved its capability to make accuracy simulations. Furthermore anyone can use this technology as it is a free software. On the following lines, research which have used this software to carry out flashover simulations is reviewed. [PERSON] et al., conducted research [44] to evaluate the accuracy of FDS 3.01 in terms of simulating this phenomenon. Full-scale experiments to validate it were carried out in a compartment similar in size to the ISO-9705 room calorimeter. Necessary heat release rates were provided by gasoline pool fire of different diameters and ventilation factors, both of which were adjusted to produce the flashover in the enclosure. The criterion to determinate whether flashover occurs was to assume to be \(\geq\)550-600 \({}^{\circ}\)C adjacent to the ceiling and \(\geq\)20 kW/m\({}^{2}\) at floor level. After performing the full-scale experiments the results were compared with the simulated flashover fires, and they showed that FDS can be used to simulate flashover. Subsequently, in the work of [PERSON] et al., a series of computational models [45] using FDS 5 code were developed to design training activities on the flashover phenomenon for firefighters of the NSW (Australian) fire brigade. In this case the criterion to determinate the occurrence of flashover was \(\geq\)600 \({}^{\circ}\)C, taken adjacent to the ceiling but not heat release rate sensor was included in the real experiment. The full-scale experiment was conducted in a shipping container with dimensions 2.4 m by 12 m by 2.6 m, which is normally used by firefighters to perform their training. Wooden boards were used as a fuel and the experiments were carried out during a training day. The simulation results concurred with the qualitative experimental data.