http://hdl.handle.net/1842/2037 2013-05-24T19:03:46Z 2013-05-24T19:03:46Z Rein, Guillermo Jahn, Wolfram Torero, Jose L http://hdl.handle.net/1842/4777 2011-02-08T15:07:03Z 2011-02-01T00:00:00Z

Title: Modelling of the Growth Phase of Dalmarnock Fire Test One Authors: Rein, Guillermo; Jahn, Wolfram; Torero, Jose L Abstract: The challenge of modelling a well characterized full-scale fire test using computational fluid dynamics is illustrated in this work comparing a priori and a posteriori simulations. In 2006, The Dalmarnock Fire Tests were conducted in two identical 3.5 m 4.75 m 2.5 m concrete enclosures with a real residential fuel load. This data set provides measured data at the highest spatial resolution available from a fire experiment to date. Prior to the tests, an international study of fire modelling was conducted in order to assess the state-of-the-art of fire simulations using a round-robin approach. Each of the seven round-robin teams independently simulated the test scenario a priori using a common detailed description of the compartment geometry, fuel packages, ignition source and ventilation conditions. Most teams decide to use the numerical code Fire Dynamics Simulator (FDSv4). Comparison to the experimental measurements showed a large scatter and considerable disparity (much larger than the error and variability associated to the experiments). The study showed that the accuracy predicting fire growth is poor. A posteriori simulations of the growth phase were conducted afterwards while having full access to all the measurements. No previous fire simulation had this large amount of data available for comparison. Simulations were compared against average and local measurements. The heat release rate is reconstructed from additional laboratory tests and upper and lower bounds for the fire growth are found. Within these bounds and after adjusting uncertain parameters, the level of agreement reached with the measurements was of 10 to 50% for the evolution of the average hot layer temperatures and between 20% and 200% for local temperatures. Description: Paper presented at Fire and Materials Conference 2011.

2011-02-01T00:00:00Z Rein, Guillermo Torero, Jose L Jahn, Wolfram Stern-Gottfried, Jamie Ryder, Noah Desanghere, Sylvain Lazaro, Mariano Mowrer, Frederick Coles, Andrew Joyeux, Daniel Alvear, Daniel Capote, Jorge A Jowsey, Allan Abecassis Empis, Cecilia Reszka, Pedro http://hdl.handle.net/1842/2704 2012-01-25T15:39:00Z 2009-03-01T00:00:00Z

Title: Round-robin study of a priori modelling predictions of the Dalmarnock Fire Test One Authors: Rein, Guillermo; Torero, Jose L; Jahn, Wolfram; Stern-Gottfried, Jamie; Ryder, Noah; Desanghere, Sylvain; Lazaro, Mariano; Mowrer, Frederick; Coles, Andrew; Joyeux, Daniel; Alvear, Daniel; Capote, Jorge A; Jowsey, Allan; Abecassis Empis, Cecilia; Reszka, Pedro Abstract: An international study of fire modelling was conducted prior to the Dalmarnock Fire Test One in order to assess the state-of-the-art of fire simulations using a round-robin approach. This test forms part of the Dalmarnock Fire Tests, a series of experiments conducted in 2006 in a high-rise building. The philosophy behind the tests was to provide measurements in a realistic fire scenario involving multiple fuel packages and non-trivial fire growth, and with an instrumentation density suitable for comparison with computational fluid dynamics models. Each of the seven round-robin teams independently simulated the test scenario a priori using a common detailed description of the compartment geometry, fuel packages, ignition source and ventilation conditions. The aim of the exercise was to forecast the fire development as accurately as possible and compare the results. The aim was not to provide an engineering analysis with conservative assumptions or safety factors. Comparison of the modelling results shows a large scatter and considerable disparity among the predictions, and between predictions and experimental measurements. The scatter of the simulations is much larger than the error and variability expected in the experiments. The study emphasises on the inherent difficulty of modelling fire dynamics in complex fire scenarios like Dalmarnock, and shows that the accuracy to predict fire growth (i.e. evolution of the heat released rate) is, in general, poor. Description: Peer-reviewed journal paper published in 2009 about the international modelling exercise conducted in 2006.

2009-03-01T00:00:00Z Koo, Sung-Han Fraser-Mitchell, Jeremy Upadhyay, Rochan Welch, Stephen http://hdl.handle.net/1842/2698 2010-08-09T13:22:45Z 2008-09-01T00:00:00Z

Title: Sensor-linked fire simulation using a Monte-Carlo approach Authors: Koo, Sung-Han; Fraser-Mitchell, Jeremy; Upadhyay, Rochan; Welch, Stephen Abstract: This study is aimed at developing a predictive capability for uncontrolled compartment fires which can be “steered” by real-time measurements. This capability is an essential step towards facilitating emergency response via systems such as FireGrid, which seek to provide fire and rescue services with information on the possible evolution of fire incidents on the scene. The strategy proposed to achieve this is a novel coupled simulation tool, based on the Monte-Carlo-based fire model, CRISP, with scenario selection achieved via comparison with (pseudo) sensor inputs. Here, some key aspects of such a system are illustrated and discussed in the context of the detailed measurements obtained in the full-scale fire test undertaken in a furnished apartment at Dalmarnock. The capability of CRISP in reproducing the fire conditions – given knowledge of the approximate heat release rate in the fire – was first verified. It is then shown that continuous selection from amongst a multiplicity of scenarios generated in Monte-Carlo fashion can be achieved, so that the predictions evolve in a way that closely follows the real fire conditions. Whilst the benefits of sensor-steering are already clearly apparent, further improvements will be possible by establishing an appropriate feedback loop between the results assessment and the parametric space in which new fires are generated, perhaps using Bayesian methods. Nevertheless, true predictive capability remains crucially dependent on the sufficient representation in the model of the mechanisms of fire growth, and this must be the focus in achieving better forecasting ability. Description: Peer-reviewed article published in the Proceedings of the 9th International Symposium on Fire Safety Science, Karlsruhe, 2008.

2008-09-01T00:00:00Z Jahn, Wolfram Rein, Guillermo Torero, Jose L http://hdl.handle.net/1842/2696 2010-08-09T14:57:34Z 2008-01-01T00:00:00Z

Title: The Effect of Model Parameters on the Simulation of Fire Dynamics Authors: Jahn, Wolfram; Rein, Guillermo; Torero, Jose L Abstract: The sensitivity of computer fire modelling using results from NIST’s Fire Dynamics Simulator (FDS) to a set of input parameters related to fire growth has been analyzed. The scenario simulated is the real-scale Dalmarnock Fire Test One and the modelling results are compared to the measurements. Fire size and location, convection, radiation and combustion parameters were varied in order to determine the associated degree of sensitivity. Emphasis is put in the prediction of secondary ignition and time to flashover. In this context and while keeping the HRR constant, simulations of fire growth are significantly sensitive to location of the heat release rate (HRR), fire area, flame radiative fraction, and material thermal and ignition properties. The simulations are relatively insensitive to the heat of combustion (while keeping the HRR constant), the soot yield and the heating from the smoke layer. The results indicate that the future development of successful fire forecast methodologies of fire growth using CFD must focus on the global HRR as well as the important parameters identified here. Description: Peer-reviewed article published in the Proceedings of the 9th International Symposium on Fire Safety Science, Karlsruhe, 2008.

2008-01-01T00:00:00Z