Results

A robust CFD-based engineering modelling methodology has been developed for evaluating thermal action on steel and composite structures. The methodology has been validated by using a systematic approach of progressive verification and validation, starting with simple fire scenarios and proceeding to more complex but practical scenarios. To ensure reliability and robustness of the methodology, every partner has contributed to the model verification and validation exercise and have managed to reproduce reasonably satisfactorily the results for each scenario. Some partners have used a selection of zone and CFD models for this purpose.

Illustrative results, comparing the model predictions with the Large Compartment fire test, are shown below:

Recommendations

Draft recommendations have been prepared covering the treatments of a range of relevant parameters in the simpler Eurocodes methodologies. The main parameters of interest are the convective heat transfer coefficient, the various emissivities, including both “fire” and “member” emissivities, the configuration factor, the effective radiative flux and the general form of the governing heat exchange equations which draw all of these factors together.

A further set of recommendations have been developed as draft “best practice” guidance for the engineering methodology developed within the current project. These extend to:

• scope - area of application, e.g. localised fire, or post-flashover fire; requirements and applicability, e.g. domain size/computational limits/cell size/accuracy balance; transient versus pseudo “steady-state” and distributed burning;
• fire/structural specific issues, such as smoke, high-temperature material properties, moisture/intumescence effects, ventilation control, fuel chemistry, etc.;
• detailed guidance on the use of CFD codes from the practitioner’s point of view, covering the determination of conservative bounds on solutions (e.g. by assuming adiabatic boundaries), choice of physical models, numerical modelling issues, guidance on the modelling process as a procedure, including sensitivity studies etc., validation work and finally some relevant case studies, perhaps based on the validation test cases studied within the scope of the current research.

More details will be provided in due course once these are approved by the ECSC F6 committee.

TRA-EFCT Workshop