Evaluation of CFD to predict smoke movement in complex enclosed spaces

Application to three real scenarios: an underground station, an offshore accommodation module and a building under construction Prepared by Health and Safety Laboratory for the Health and Safety Executive 2004 RI, TD and OD HSE divisions have jointly commissioned HSL to investigate the capabilities and limitations of Computational Fluid Dynamics (CFD) to predict the transport of smoke in complex enclosed spaces. Despite a lack of validation for this application, CFD is increasingly used in safety cases as a predictive tool to demonstrate the effectiveness of modern building designs and/or emergency ventilation to control the movement of smoke in the event of a fire. To meet the objective, HSL has undertaken a research project combining CFD modelling and experiments. The work consisted of three distinct phases: Phase 1 comprised CFD calculations relating to three real " complex spaces ". These were an underground station, an accommodation module on an offshore platform and a high rise building under construction. Different CFD modelling approaches were used to investigate their effect on the prediction of smoke movement. The particular modelling approaches tested were representative of those being employed in fire safety engineering. Phase 2 produced a " benchmark " dataset of experimental measurements of the movement of hot smoke in simple small scale structures. A range of basic geometries were constructed, instrumented and tested, each addressing a particular aspect of the physical behaviour of smoke layers. While the experiments were deliberately simplified to concentrate on the fundamental of smoke movement, the geometries were similar to those found in the three real cases-corridors/tunnels, both horizontal and sloping, larger open spaces and tall atria. Phase 3 was a detailed examination of CFD performance in modelling the phase 2 benchmark experiments. The specific aspects of the modelling process were varied, such as the computational grid, and the discretisation scheme. The results of each calculation were compared with measurements, allowing the level of agreement to be quantified. The results of the different modelling approaches were also compared to quantify their relative effects. The present report contains the description and conclusions of the work related to Phase 1, the modelling of three real scenarios by different approaches. This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy. All rights reserved. No part …