# Computational Fluid Dynamics of Compartent Fires: A Review of Methods and Applications
## 3 CFD Simulation in Compartment Fires  
As shown in Figure 1, a fire in enclosed spaces contains several stages with different properties. Therefore, it is necessary to simulate all the stages from start to end, while using CFD simulation. [PERSON] et al. [2] reviewed the CFD modeling used in process safety including compartment fires, jet fires, pool fires, gas diffusion, explosions, etc. Besides that, they also referred to the idea that CFD simulations should be validated only based on the available experimental data. This point, which is mentioned earlier by the authors in the introduction (blind simulation) when there is no experimental measurement available, presents an obstacle in the way of CFD applications. However, CFD simulation is still an accurate and reliable tool to predict the overall behavior of the fire and possible risks, even though it is not validated. [PERSON] et al. [24] presented the critical role of HRR in CFD simulations of fires in enclosed compartments and outlined the complexities and limitations of current modeling approaches. They proposed that coupling combustion models with radiation models and accounting for extinction and re-ignition behavior in CFD is important for accurately predicting HRR. It was found that accurate prediction of transient phenomena in fires, such as oscillations in pressure and temperature due to variation in HRR, is one of the key challenges. Furthermore, determining HRR becomes complicated by feedback loops involving flame heat transfer, fuel pyrolysis, and compartment boundaries in solid and liquid fuels. As mentioned earlier, this research is mainly considered as an overview of CFD modeling, and the existing methods used for the case of compartment fires. There have already been some reviews [2; 5; 7] of the research and methodologies and some challenges in the current path have been presented. While looking for reliable resources, two main categories were highlighted: (1) investigation of different sub-models and the comparison between them and (2) sensitivity analysis. Sensitivity analysis in fire modeling is defined as the influence of the input parameters on the simulation results in CFD tools. [PERSON] et al. [25] conducted a sensitivity analysis for a compartment fire using ISIS. They studied the influence of some input factors on the simulation results. It was shown  
Figure 2: Schematic view of the interaction between the simulation, model, and validation. Adopted from SCS technical report [23]. that the turbulence model constant as well as combustion parameters (e.g., efficiency) had the most impact on simulation outputs (e.g., gas temperature), while the soot absorption coefficient, constant parameters in combustion modeling, and Prandtl number have a low impact on outputs. This can be useful in CFD simulations where no detailed information is provided and some variables must be assumed. [PERSON] et al. [17] investigated compartment with liquid pool fire (dodecane) numerically and compared the semi-blind and open simulation for HRR and ventilation. Pyrolysis and fan curve were used in semi-blind simulation, while the experimental measurements for HRR and ventilation were used in the open simulation. Their results showed that a pyrolysis model in a blind simulation predicts a higher peak value and earlier fire extinction time than experimental data, as shown in Figure 3. There was no significant difference between different methods of ventilation modeling. One of the recent reviews on fire modeling by CFD has been conducted by [PERSON] [5]. She reviewed the achievements in sub-models including combustion, heat transfer, and pyrolysis, while presenting two relevant challenges which modelers and researchers may encounter: (1) upscaling the fire simulation without the need to simplify the sub-models and expanding mesh grid sizes, compared to simulations in smaller scale, and (2) the unavailability of reliable experimental data to validate the CFD simulations.