Designing an experimental rig for developing a fire severity model using numerical simulation

Summary In this study, an experimental rig representing a deep enclosure was designed to be used to validate a CFD‐based fire model in predicting the outcome. The model then can be used for further study to investigate physical phenomenon within a deep enclosure and to develop an engineering fire severity (heat release rate, HRR, vs time vs position [1]) model. Two empirical models (the VU model [1] and Kawagoe model [2]) were used along with Fire Dynamics Simulator (FDS) in designing the experimental rig. For a specific‐sized enclosure, when the HRR was prescribed to the FDS as input from the VU model, it was accurately reproduced, while the HRR from the Kawagoe was used as the input, the FDS calculated much lower value. The experimental rig of that specific size was then built, and various parameters were measured from the tests with liquid fuel fire within this experimental rig. The measured HRR was prescribed into the FDS, and the FDS could reproduce HRR values well. However, the predicted temperature and radiation flux was not as good, especially when the flames were near the opening. This may be due to the tendency of flames over‐projecting outside the opening in FDS simulations.