Toward predictive simulations of pool fires in mechanically ventilated compartments

Abstract The objective of this work is to propose an effective modeling to perform predictive simulations of pool fires in mechanically ventilated compartments, representative of a nuclear installation. These predictive simulations have been conducted using original boundary conditions (BCs) for the fuel mass loss rate and the ventilation mass flow rate, which depend on the surrounding environment. To validate the proposed modeling, the specific BCs were implemented in the ISIS computational fluid dynamics (CFD) tool, developed at IRSN, and three fire tests of the PRISME-Door experimental campaign were simulated. They involved a hydrogenated tetrapropylene (HTP) pool fire in a confined room linked to another one by a doorway; the two rooms being connected to a mechanical ventilation system. The three fire scenarios offer different pool fire areas (0.4 and 1 m 2 ) and air change rates (1.5 and 4.7 h −1 ). For the one square meter pool fire test, the study presents, in detail, the effects of the boundary conditions modeling. The influence of the ventilation and fuel BCs is analyzed using either fixed value, or variable, function of the surrounding environment, determined by a Bernoulli formulation for the ventilation mass flow rate and by the Peatross and Beyler correlation for the fuel mass loss rate. The results indicate that a full coupling between these two BCs is crucial to correctly predict the main parameters of a fire scenario as fire duration, temperature and oxygen fields, over- and under-pressure peaks in the fire compartment. Variable BCs for ventilation and fuel rates were afterward both used to predictively simulate the fire tests with a pool surface area of 0.4 m 2 . The predicted results are in good agreement with measurements signifying that the model allows to catch the main patterns characteristic of an under-ventilated fire.

[1]  L. Rigollet,et al.  Quantifying differences between computational results and measurements in the case of a large-scale well-confined fire scenario , 2011 .

[2]  Laurent Audouin,et al.  Effects of vitiation on the heat release rate in mechanically-ventilated compartment fires , 2008 .

[3]  Vytenis Babrauskas,et al.  Estimating large pool fire burning rates , 1983 .

[4]  L. Rigollet,et al.  Verification and validation of a CFD model for simulations of large-scale compartment fires , 2011 .

[5]  Vasily Novozhilov,et al.  CFD PREDICTION OF POOL FIRE BURNING RATES AND FLAME FEEDBACK , 2004 .

[6]  L. Rigollet,et al.  Validation process of ISIS CFD software for fire simulation , 2012 .

[7]  L. Rigollet,et al.  Analytical Approach for Predicting Effects of Vitiated Air on the Mass Loss Rate of Large Pool Fire in Confined Compartments , 2011 .

[8]  M. Pinar Mengüç,et al.  Thermal Radiation Heat Transfer , 2020 .

[9]  S. Suard,et al.  Fuel Mass-Loss Rate Determination in a Confined and Mechanically Ventilated Compartment Fire Using a Global Approach , 2011 .

[10]  James A. Sethian,et al.  THE DERIVATION AND NUMERICAL SOLUTION OF THE EQUATIONS FOR ZERO MACH NUMBER COMBUSTION , 1985 .

[11]  M. G. Zabetakis,et al.  Research on hazards associated with production and handling of liquid hydrogen. [Fire hazards and formation of shock-sensitive condensed mixtures] , 1961 .

[12]  Yunyong Utiskul.  Theoretical and experimental study on fully-developed compartment fires , 2006 .

[13]  T. F. Smith,et al.  Evaluation of Coefficients for the Weighted Sum of Gray Gases Model , 1982 .

[14]  S. Patankar,et al.  Finite volume method for radiation heat transfer , 1994 .

[15]  Takashi Kashiwagi,et al.  A global model for predicting the burning rates of liquid pool fires , 1999 .

[16]  Jason Floyd.  COUPLING A NETWORK HVAC MODEL TO A COMPUTATIONAL FLUID DYNAMICS MODEL USING LARGE EDDY SIMULATION , 2011 .

[17]  James G. Quintiere,et al.  A theory for flame extinction based on flame temperature , 2004 .

[18]  Jean-Claude Latché,et al.  An L2‐stable approximation of the Navier–Stokes convection operator for low‐order non‐conforming finite elements , 2011 .

[19]  M. J. Peatross,et al.  Ventilation Effects On Compartment Fire Characterization , 1997 .

[20]  A. Snegirev,et al.  Statistical modeling of thermal radiation transfer in buoyant turbulent diffusion flames , 2004 .

[21]  G. D. Raithby,et al.  A Finite-Volume Method for Predicting a Radiant Heat Transfer in Enclosures With Participating Media , 1990 .

[22]  R. Rannacher,et al.  Simple nonconforming quadrilateral Stokes element , 1992 .

[23]  J. M. Such,et al.  Effect of ventilation procedures on the behaviour of a fire compartment scenario , 2005 .

[24]  G. Cox,et al.  Combustion fundamentals of fire , 1995 .

[25]  Vb Novozhilov,et al.  Computational fluid dynamics modeling of compartment fires , 2001 .