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    STP1593

    Parametric Study of Fabric Characteristics' Effect on Vertical Flame Test Performance Using Numerical Modeling

    Published: 2016


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    Abstract

    A parametric study of fabric characteristics' effect on performance in the standard vertical flame test (VFT; ASTM D6413) is conducted using computational fluid dynamics modeling. This bench-top test is used for characterizing fire performance of textiles during the fabric design stage to determine flame resistance. The advantage of utilizing modeling to study fire performance of textiles during VFT is the ability to conduct detailed studies of the effect of fabric characteristics on flame spread. First, two textile materials are chosen for modeling that exhibit two limit cases: either complete flame spread (nylon 6,6/cotton fiber fabric; NYCO) or self-extinguish (flame-retardant rayon/nylon 6,6/para-aramid fiber fabric; FR Army combat uniform) in the VFT. Parameter estimation for various model parameters—kinetic parameters and heat of reactions, heat of combustion, thermophysical parameters, and optical parameters—is performed for these samples by combination of independent measurements and numerical optimization using bench-scale experimental data. Second, parametric analysis is conducted for these two cases. The parameter values are varied one at a time, and their effect on the pyrolysis modeling (one-dimensional cone test simulation) and the flame spread modeling (three-dimensional VFT simulation) are analyzed. Based on this work, the parameters that are significantly sensitive to modeling outputs (i.e., switch from complete flame spread to self-extinction or vice versa) are identified. Third, understanding the sensitive parameters in this VFT modeling with fabric samples, a new sample is modeled—flame-retardant cotton fiber fabric, FR cotton. The modeling results show that numerical modeling is capable of capturing the fire characteristics of a fabric sample when parameters are carefully estimated, especially the sensitive parameters. Understanding the effects of fabric characteristics on different fire behaviors observed in the standard VFT through numerical modeling will help designers more efficiently and effectively develop fire-safe fabrics.

    Keywords:

    computational fluid dynamic (CFD) modeling, vertical flame test, comprehensive pyrolysis modeling, kinetic modeling, parameter estimation, textile


    Author Information:

    Kim, Esther
    U.S. Army Natick Soldier Research, Development and Engineering Center, Natick, MA

    Dembsey, Nicholas
    WPI Fire Protection Engineering, Worcester, MA

    Godfrey, Thomas A.
    U.S. Army Natick Soldier Research, Development and Engineering Center, Natick, MA


    Committee/Subcommittee: F23.50

    DOI: 10.1520/STP159320160005