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In fire simulations, it is essential to include detailed chemical kinetics for the description of the combustion process where intermediate chemical products are formed through a series of elementary reactions. A novel in-house fire field model based on Large Eddy Simulations (LES) approach incorporating fully coupled subgrid-scale (SGS) turbulence, combustion, soot formation and radiation models for the interactive and non-linear nature of the turbulent reacting flow in compartment fire phenomena has been developed in this article. It uniquely embraces the detailed reaction mechanisms for the chemical processes involved during combustion. Since the modelling of hydrocarbons by-products are enabled when considering the full chemical profile, the formation of soot particles can be related to the concentration of main incipient such as acetylene, which provides an appropriate representation of nucleation, surface growth processes. The significance of the improvement of soot particles modelling had been numerically investigated applying three different two-equations semi-empirical soot models: (i) Moss model (simplified model taken the fuel as the soot precursor); (ii) Moss-Brookes model (considers acetylene as the soot precursor) and (iii) Moss-Brookes-Hall model (considers acetylene, benzene ring and phenyl radical as the soot precursors). Comprehensive temperature and soot measurements from fire tests in a full-scale ISO compartment constructed purposely with a small opening gap to create the under-ventilated fire condition with which the effect of soot particles generation would be more significant. The computed results were compared with measured results for validation of the implemented soot models. [ABSTRACT FROM AUTHOR]

A novel in-house computation code based on large eddy simulations (LES) incorporating fully coupled subgrid-scale (SGS) turbulence, combustion, soot and radiation models for turbulent reacting flows in compartment fires has been developed. It uniquely embraces the detailed reaction mechanisms for the chemical processes involved during combustion, which provides a comprehensive description of the fuel oxidation processes. Furthermore, it gives a more complete representation of the generation of intermediate chemical by-products including toxic gases such as carbon monoxide and irritant gases such as soot. Since the modelling of hydrocarbons by-products are enabled when considering the full chemical profile, the formation of soot particles is correlated to the concentration of main soot incipient acetylene, which provides an appropriate representation of nucleation, surface growth processes. The LES code has been validated with experimental fire tests results for both ventilated and under-ventilated fires in compartment for confirmation of its robustness. The importance of incorporating the detailed reaction mechanisms in compartment fire simulations has been confirmed by comparing with experiments. For under-ventilated fires in compartment, the chemical kinetics become increasingly important since the combustion efficiency drops significantly involving generation of intermediate chemical species. It is discovered that species concentrations especially CO 2 and CO are more accurately predicted by the detailed scheme comparing to the multi-step scheme, since the formation of hydrocarbons and nitrogen oxides are considered. In general, the simulation incorporating detailed kinetics showed an averaged improvement of 9.2% and 81.7% in the prediction of CO 2 /CO ratio and volume fraction of soot respectively. This also improves the replication of the flame structure as the fire is chemically-driven within the combustion zone. [ABSTRACT FROM AUTHOR]

• Underventilated ISO9705 room fire with various fuel location configurations is studied. • Detailed kinetics combustion model was coupled with a C 2 H 2 based soot model. • Influence on CO/CO2 enclosure distribution owing to the fuel pan configurations is studied. • Multiple pool fire in enclosure is characterised by considering fuel pan distance. • Single stand fires and multiple pool fires under enclosure fire conditions are compared. A set of numerical analyses was conducted to investigate the effect of fuel location of dual burners in an under-ventilated ISO9705 compartment room. Moreover, the influences of the burner separation displacement on the fire development, the evolution of thermal layers, the distribution of toxic gas species were comprehensively studied. The simulations were conducted using a novel in-house large eddy simulation (LES) based fire field model comprised of subgrid-scale (SGS) turbulence, detailed chemical kinetics of combustion, soot and radiation models. The first part of the simulation focused on 3 different fuel distributions: single centre burner (SCB), single rear burner (SRB) and two distributed burner (TDB). Alternative configurations were considered for dual burners with 4 different distances between the dual burners, to study the influence towards air flow at the doorway, internal temperature profile and major chemical species (i.e. CO/CO 2) distributions. The numerical outcome states that fuel distribution has a minor effect on heat release rate and the total CO 2 amount but noticeable differences in CO's generation and distribution. Overall, the temperature and gas field predictions were almost identical for all dual burner cases, while significant differences were observed at the rear section of the compartment, especially temperature, CO/CO 2 vol fraction and soot concentration. [ABSTRACT FROM AUTHOR]

• Full-scale compartment room fire with varies opening size is studied. • Detailed kinetics combustion model was coupled with a C 2 H 2 based soot model. • Fire tilting angle is characterised by considering thermal reacting air/fuel mixture. • Influence on CO/CO2 enclosure distribution owing to the deflected flame is studied. • Ventilated and under-ventilated compartment room fire conditions are investigated. Numerical assessment on a large-scale compartment buoyant fires was performed to investigate the effect of exit door width on the flame tilting behaviour, evolution of the thermal layer and formation of combustion species. The simulations were performed using an in-house large eddy simulation (LES) based fire field model incorporating subgrid-scale (SGS) turbulence, detailed chemical kinetics combustion, soot and radiation models. A comprehensive set of simulation case studies have been carried out with various doorway opening sizes, to investigate the influence of the incoming air entrainment towards the deflection angle of the flame. In addition, the changes in the thermal interface, neutral plane and major chemical species profiles (i.e. CO/CO 2) are also studied in detail. The fire model was validated against experimental measurements. It was found that increasing the door width elevates the neutral plane height and its correlated layer height of concentrated toxic gases. In addition, there is a critical door width (4/6) that produced the minimum fire tilting angle, deviation from the minimum door width results in an increase in flame tilting angle. It was discovered the centre fire have a range of titling angle between 58° to 75°, with a variation of 25% from 2/6 to 8/6 doorway sizes. This also totally affects the dynamics of the CO 2 profiles with the compartment room, in which the concentrated toxic gas layer ascends as the fire is more ventilated. In general, it was discovered that having a large doorway size is mainly contributing to reduce the potential fire hazards in a one-opening compartment room fire scenario. The relation of compartment fire tilting can be critical especially for the design of fire protection systems. [ABSTRACT FROM AUTHOR]