Recent studies suggest the assumption of uniform heating that is used in current structural fire design cannot be assumed conservative, especially if the fire is expected to burn locally. Aside from design equations, which have limited applicability, a common approach to simulating structural members subjected to a localized fire is modeling the fire‐structure interaction using a coupled computational fluid dynamics (CFD)‐finite element (FE) model. In the existing literature, a wide range of methods and parameters are used when determining the boundary conditions at the fire‐structure interface, specifically regarding the representation of net heat flux, heat transfer coefficient, and surface emissivity of steel. The purpose of this study is to investigate various methods for representing the boundary conditions in terms of accuracy and computational efficiency and then identify best practices. In conclusion, our study found that net heat flux predicted by adiabatic surface temperature, a nonconstant heat transfer coefficient, and a surface emissivity of 0.9 for steel was the most reliable thermal boundary condition in a coupled CFD‐FE model of a localized fire. These recommendations are based on the two cases studied here, and caution should be used when applying these results to future studies.

中文翻译：

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局部火灾导致的结构边界条件建模的最佳做法

最近的研究表明，当前结构火灾设计中使用的均匀加热的假设不能被保守，特别是如果预期火灾会在局部燃烧的话。除了适用性有限的设计方程式之外，用于模拟遭受局部火灾的结构构件的常用方法是使用耦合计算流体动力学（CFD）-有限元（FE）模型对火灾与结构的相互作用进行建模。在现有文献中，当确定火结构界面的边界条件时，会使用各种各样的方法和参数，特别是关于净热通量，传热系数和钢的表面发射率的表示。这项研究的目的是研究各种方法来代表边界条件的准确性和计算效率，然后确定最佳实践。总之，我们的研究发现，在绝热的耦合CFD-FE模型中，由绝热表面温度，非恒定传热系数和0.9的表面发射率预测的净热通量是最可靠的热边界条件。这些建议基于此处研究的两种情况，在将这些结果应用于未来研究时应谨慎行事。在局部火灾的耦合CFD-FE模型中，钢的9是最可靠的热边界条件。这些建议基于此处研究的两种情况，在将这些结果应用于未来研究时应谨慎行事。在局部火灾的耦合CFD-FE模型中，钢的9是最可靠的热边界条件。这些建议基于此处研究的两种情况，在将这些结果应用于未来研究时应谨慎行事。