“Will you stand up in the court and defence your fire model?”,- was the question asked by Professor Rubini at the lectures on Simulation of Fires in Enclosures back in January. I did not know much about modelling of fires before taking this course, but now I know that it can be a very powerful tool if used with caution. Fire modelling can be used analyze a range of concepts including ignition, flames, plume, smoke and etc. for the purposes of life safety, structural behaviour, investigations, risk and many more. But complex nature of the fire phenomenon and inadequacy of computer power set limitations to the fire modelling, that is why it is important to know both capabilities and shortcomings of the modelling tools.
Fire scenario (credits to the Lecture slides by Dr.Philip Rubini)
Currently, there are a number of CFD software (not Confusion For Dummies), and we were introduced to the Fire Dynamics Simulator or simply FDS, which is commonly used for fire applications. It is free, so everyone can access it, and potentially become an expert in using it. But, to ensure that results are credible it is important to verify and validate computational simulations, as well as check the sensitivity of the model to the parameters. Also, we were introduced to the famous Philip’s Rules which state “No grid, no solution”, “If you haven’t filled your computer you are not trying hard enough”, “Garbage in-garbage out”, and “A report of a CFD simulation without discussion of error is of little value”. I think these rules can be very useful and should be kept in mind before building the model.
CFD user (credits to the Lecture slides by Dr.Philip Rubini)
To conclude, by taking this course, we got an insight into the fire modelling world. In the future, we might be able to improve the simulations by using more powerful computers, but as for now, we need to be fully aware of the current limitations.
FDS simulation of the Steckler room fire experiment.