# Computational Fluid Dynamics of Compartent Fires: A Review of Methods and Applications
## 3 CFD Simulation in Compartment Fires
### Physical Models
#### 3.3.3 Combustion and Kinetics
Although, since the fuel decomposition is not certain, assuming single input yields does not predict the combustion characteristics precisely [7]. Comparing the EDC combustion model with standard EDM in a methanol pool fire, [PERSON] et al. [86] revealed that EDM could not predict the flame temperature, even with major justification of the EDM coefficients compared to EDC. In a similar work, [PERSON] et al. [87] compared the EDM and IFC for simulating a pool fire in FireFOAM and the results indicated that the latter over-predicts the velocity and temperature and the former can simulate the combustion more accurately due to its adoption of the time characteristic of turbulence and diffusion. EDM is the better choice in predicting velocity with OneEqEddy SGS model, and IFC is more reliable when using the Smagorinsky approach. [PERSON] et al. [53] used the FGM combustion model and compared the simulation results with IFC and EDM. Although IFC and EDM provided more accurate temperature predictions, FGM was more precise in simulating different species. Moreover, it was recommended to include radiation effect in FGM to improve the results. Authors studied the FGM ability in compartment and pool fire simulations and investigated the effects of considering radiative heat transfer [88]. It was shown that combustion-radiation coupling enhanced model accuracy in a pool fire scenario. Compartment fire modeling was not influenced much by radiation coupling, although the results showed better agreement with experimental data. In addition, IFC and EDM are not able to model the extinction, while FGM is. [PERSON] et al. [75] simulated an enclosed clean room fire using three different combustion models, namely VHS, EBU, and presumed probability density function (prePDF), in which a PDF is used to consider turbulence chemistry interaction. Their results demon strated that prePDF was the best choice, while VHS was the worst in the case of temperature prediction for large fires. Considering computation time, EBU had the longest one and VHS had the shortest. A comparative study on fast chemistry-based combustion models for pool fires was conducted by [PERSON] et al. [89]. Among IFC, EDM, EDC, and steady laminar flamelet model (SLFM), SLFM was more capable of predicting the mean turbulent kinetic energy, while EDM predicted the mean vertical velocity of the flow more accurately. [PERSON] et al. [90] used two EDC models (1981 and 2005) with infinitely fast and finite-rate chemistry (1, 2, and 6 steps combustion) to simulate pool fires. The results showed that infinitely fast chemistry was less grid sensitive, since the reaction rates in finite-rate chemistry depend non-linearly on the resolved quantities such as mass fraction and temperature. In addition, EDC 1981 produced lower reaction rates and temperature compared to EDC 2005; the reason for this being that unburnt fuel tends to exit the domain, which reduced the heat release rate. Six steps predicted the temperature more accurately than the two-step reaction mechanism. However, more detailed mechanisms caused more fuel to be escaped, resulting in lower HRR. However, six-step mechanism predicted species and flame temperature more precisely. Regarding the importance of kinetics in fire modeling, [PERSON] and [PERSON] [91] presented the detailed kinetics for combustion, consisting of 112 reaction steps and 37 species which can enhance the model performance in predicting temperature and species. Furthermore, [PERSON] et al. [92] developed a computation code and studied the comparison between detailed and multi-step chemical kinetics for combustion in compartment fires with different ventilation modes. Their results showed that multi-step kinetics over-predict CO\({}_{2}\) and CO concentration. Although in well-ventilated compartment fire, CO\({}_{2}\) and CO concentration were predicted reasonably, they were over-predicted in under-ventilated fires using detailed kinematics.