Modeling Heat Transfer in Thin Fire Blanket Materials under High External Heat Fluxes

To investigate the performance of thin fire blanket materials for house protection from wildland fires, a one-dimensional numerical model, which combines conductive and radiative heat transfer, has been developed, solved and compared with bench-scale experiments. Two types of incident heat sources are studied: convective heating from a burner flame and radiative heating from a cone heater. Radiative heat exchange between the blanket and the environment is critical in the performance of the blankets at high temperatures. The treatment of radiation includes the solution of the radiative transfer equation by the discrete ordinate method since in-depth absorbing, emitting and scattering are believed to be important in these thin blanket materials. A number of material combinations were tested and analyzed, including single and double layers of fiberglass fabric with and without aluminum foil on the front and back surfaces. It is found that high heat-blocking efficiencies can be obtained using thin blankets. Interestingly, it is also found that protecting a house from convective heating is a more difficult challenge than protecting it from radiant heating.

[1]  C. Tien,et al.  Radiative Heat Transfer in Fibrous Insulations—Part II: Experimental Study , 1983 .

[2]  T. Love,et al.  Direct determination of gray participating thermal radiation properties of insulating materials , 1987 .

[3]  Patirop Chitrphiromsri,et al.  Modeling heat and moisture transport in firefighter protective clothing during flash fire exposure , 2003 .

[4]  Frank P. Incropera,et al.  Fundamentals of Heat and Mass Transfer , 1981 .

[5]  William Mell,et al.  A Heat Transfer Model for Firefighters' Protective Clothing , 2000 .

[6]  S. Lee.  Scattering phase function for fibrous media , 1990 .

[7]  Michael F. Modest,et al.  Narrow-band and full-spectrum k-distributions for radiative heat transfer—correlated-k vs. scaling approximation , 2003 .

[8]  V. A. Petrov,et al.  Combined radiation and conduction heat transfer in high temperature fiber thermal insulation , 1997 .

[9]  A. Abdel-azim.  Fundamentals of Heat and Mass Transfer , 2011 .

[10]  David A. Torvi,et al.  Heat Transfer Model of Flame Resistant Fabrics During Cooling After Exposure to Fire , 2006 .

[11]  T. W. Tong,et al.  Analytical Models for Thermal Radiation in Fibrous Insulations , 1980 .

[12]  T. W. Tong,et al.  Radiative Heat Transfer in Fibrous Insulations—Part I: Analytical Study , 1983 .

[13]  G. Song,et al.  Investigation of Feasibility of Developing Intelligent Firefighter-Protective Garments Based on the Utilization of a Water-Injection System , 2006 .

[14]  Roger L. Barker,et al.  Modeling the Thermal Protective Performance of Heat Resistant Garments in Flash Fire Exposures , 2004 .

[15]  David A. Torvi,et al.  Heat Transfer in Thin Fibrous Materials Under High Heat Flux , 1999 .