Quantifying differences between computational results and measurements in the case of a large-scale well-confined fire scenario

Audouin, L.; Chandra, Laltu; Consalvi, Jean-Louis; Gorza, E.; Hohm, Volker; Hostikka, Simo; Ito, Tokiko; Klein-Heßling, W.; Lallemand, Christine; Magnusson, T.; Noterman, N; Park, J.S.; Peco, J.; Rigollet, L.; Suard, Sylvain; Hees, Patrick Van

doi:10.1016/j.nucengdes.2010.10.027

Cited by 57 publications

(37 citation statements)

References 8 publications

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“…Expensive as that might be, it is a worthwhile investment on the long term to pursue small-scale, intermediate-scale and full-scale set-ups, because they all provide valuable and complementary information for the engineer, who has no other choice than to run. Examples of recent 'realistic' full-scale experiments are the 'Dalmarnock' tests [27], car park fire tests [28,29], the 'Rabot' apartment fire tests [30] and the PRISME tests [31]. A complex problem is tackled and the experiments and simulations are set up with great care, such that one can learn from 'crashes' while running.…”

Section: Different Types Of Experimentsmentioning

confidence: 99%

Computer Modeling for Fire and Smoke Dynamics in Enclosures: A Help or a Burden?

Merci¹

2014

Fire Saf. Sci.

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Fire simulations are of unique value in different respects: for fire safety system design calculations, for improving our understanding (theory and model development and validation) and for fire forecasting. In this paper the effective use of computing power for the further development of fire safety science is discussed, considering only gas phase phenomena in fire and smoke dynamics in enclosures. Arguably, much effort needs to be devoted to multi-phase phenomena (pyrolysis modeling, the effect of water or other suppressants, etc.), but this is not discussed in the paper at hand.A common feature to all types of simulations is that the Required Computing Resources (RCR), determined by the envisaged accuracy and the complexity of the problem to be tackled, must be less than the Available Computing Resources (ACR). Accuracy, reliability and dimensionality of the models used, must therefore be related to the problem tackled. In order to make progress, bench-marking studies, as a joint effort made by modelers and experimentalists, with transparent communication, are argued to be a good approach for systematic progress in the development of, and confidence in, models.Using Computational Fluid Dynamics (CFD) can be very valuable for the development of theory and the study of detailed fluid mechanics phenomena, but several aspects are important to guarantee the quality of the results. Some ideas will be formulated on how to investigate requirements on the computational mesh. Turbulence -chemistry interaction (TCI) and turbulence -radiation interaction (TRI) are also discussed briefly. Yet, it is argued that a major source of uncertainty in computer simulations stems from (and will continue to stem from) the characterization of the ever changing and developing materials (i.e. the fuel), as well as from geometry dependent features (including ventilation and heat transfer). This affects the combustion and soot formation, and therefore the fire and smoke dynamics. Therefore, a user-defined fire will remain indispensible in the foreseeable future when using computer modeling for the sake of design of fire safety systems. Once this fire has been defined, CFD is best suited in regions where detail is required or complex flow patterns establish, while other forms of modeling can be considered in other regions.For real-time and forecasting applications, it is argued that sensor-assisted numerical simulations are very promising and their use is expected to become widespread in the coming decades. With increasing computing power, the use of CFD will become more feasible in this context, but for the time being zone model calculations (perhaps combined with CFD in regions where more detail is required) seem better suited to that purpose.

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Section: Different Types Of Experimentsmentioning

confidence: 99%

Computer Modeling for Fire and Smoke Dynamics in Enclosures: A Help or a Burden?

Merci¹

2014

Fire Saf. Sci.

View full text Add to dashboard Cite

show abstract

“…Figure 3에 제시된 단위 면적당 질량손실율을 통해 이루어졌으며, 이때 TPH 연료의 연소 열(heat of combustion)은 42,000 kJ/kg (18) 으로 설정되었다. 비록 실험에서는 원형 팬이 사용되었으나, FDS는 직선으 로 형성된 격자계(rectilinear grid system)만을 허용하기 때문에 동일 면적의 정사각형 화원으로 대체하였다.…”

Section: 계산방법 및 조건unclassified

Validation of FDS for Predicting the Fire Characteristics in the Multi-Compartments of Nuclear Power Plant (Part I: Over-ventilated Fire Condition)

Mun¹,

Hwang²,

Park³

et al. 2013

Journal of Korean Institute of Fire Science and Engineering

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The Fire Dynamics Simulator (FDS) has been applied to simulate a full-scale pool fire in well-confined and mechanically ventilated multi-compartments representative of nuclear power plant. The predictive performance of FDS was evaluated through a comparison of the numerical data with experimental data obtained by the OECD/NEA PRISME project. To identify clearly the FDS results regarding to the user-dependence in the process of FDS implementation except for the intrinsic limitation of FDS such as simple combustion model, only the over-ventilated fire condition was chosen. In particular, the importance of accurate boundary conditions (B.C.) in mechanically ventilated system were discussed in details. It was known from FDS results that the B.C. on inlet and outlet vents did significantly affect the thermal and chemical characteristics inside the compartments. Finally, it was confirmed that the FDS imposed an accurate ventilation B.C. provided qualitatively good agreement with temperatures, heat fluxes and concentrations measured inside the nuclear-type multicompartments.

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“…화원에 대한 입력값은 Figure 3에 제시된 단위 면적당 질량손실율을 통해 산출되었으며, 이때 TPH 연료의 연소 열(heat of combustion)은 42,000 kJ/kg (13) 으로 설정되었다. 비록 실험에서는 원형 팬이 사용되었으나, FDS는 사각형 격자계(rectilinear grid system)만을 허용하기 때문에 동일 면적의 정사각형 화원으로 대체하였다.…”

Section: 실증 실험 및 수치해석 방법unclassified

Validation of FDS for Predicting the Fire Characteristics in the Multi-Compartments of Nuclear Power Plant (Part II: Under-ventilated Fire Condition)

Mun¹,

Hwang²,

Park³

et al. 2013

Journal of Korean Institute of Fire Science and Engineering

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The validation of Fire Dynamics Simulator (FDS) was conducted for the under-ventilated fire in well-confined multicompartments representative of nuclear power plant. Numerical results were compared with experimental data obtained by the OECD/NEA PRISME project. The effects of the numerical boundary conditions (B.C.) in ventilated system and the flame suppression model applied within FDS on the thermal and chemical environments inside the compartment were discussed in details. It was found that numerical B.C. on the vent flow resulting from over-pressure at ignition and underpressure at extinction should be considered carefully in order to predict accurately the species concentrations rather than temperatures and heat fluxes inside the multi-compartment. The default information of suppression model applied within FDS resulted in artificial phenomena such as flame extinction and re-ignition, and thus the FDS results on the under-ventilated fire showed good agreement with the experimental results as the modified suppression criteria of the fuel used was adopted.

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Quantifying differences between computational results and measurements in the case of a large-scale well-confined fire scenario

Cited by 57 publications

References 8 publications

Computer Modeling for Fire and Smoke Dynamics in Enclosures: A Help or a Burden?

Computer Modeling for Fire and Smoke Dynamics in Enclosures: A Help or a Burden?

Validation of FDS for Predicting the Fire Characteristics in the Multi-Compartments of Nuclear Power Plant (Part I: Over-ventilated Fire Condition)

Validation of FDS for Predicting the Fire Characteristics in the Multi-Compartments of Nuclear Power Plant (Part II: Under-ventilated Fire Condition)

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