Advancing the Prediction of Evaporation Rate of Liquid Pool Fires in Mechanically Ventilated Compartments Using Computational Fluid Dynamics

The propagation of smoke and hot gases in mechanically ventilated nuclear compartments has been highlighted as one of the main issues of significance. It may lead to the failure of several systems such as clogging of filters located in the ventilation network or electrical devices. To address this issue, the continuous improvement of the predictive capability of existing models with regards to liquid pool fires is of high importance. Computational fluid dynamics (CFD) is widely used for fire simulations. It is worth noting that most pool fire simulations in open atmosphere, under-ventilated and mechanically ventilated compartments have relied on pre-defined/prescribed fuel mass loss rate (MLR) or heat release rates (HRR) from correlations or experimental data when available. Therefore, the prediction of fuel MLR and HRR based on the specific actual fire conditions rather than prescribed data, remains a key development area for the fire community. The present work aims to provide some contribution and advances on this issue. Building on existing liquid evaporation models, the study develops an approach which in then implemented in an in-house version of the CFD code FireFOAM in which a mechanical ventilation model has been embedded, to predict the fuel MLR in both open atmosphere and mechanically ventilated compartments. Validations of the implemented model includes comparison with experimental fuel MLR and previous studies that made use of correlations and experimental data. The results show acceptable fuel MLR predictions with reasonable accuracy and provide further insights into fire behaviour in mechanically ventilated compartments.