The ‘Balbi model’ is a simplified steady-state physical propagation model for surface fires that considers radiative heat transfer from the surface area of burning fuel particles as well as from the flame body. In this work, a completely new version of this propagation model for wildand fires is proposed. Even if, in the present work, this model is confined to laboratory experiments, its purpose is to be used at a larger scale in the field under operational conditions. This model was constructed from a radiative propagation model with the addition of a convective heat transfer term resulting from the impingement of packets of hot reacting gases on unburnt fuel elements located at the base of the flame. The flame inside the fuel bed is seen as the ‘fingers of fire’ described in the literature. The proposed model is physics-based, faster than real time and fully predictive, which means that model parameters do not change from one experiment to another. The predicted rate of spread is applied to a large set of laboratory experiments (through homogeneous pine needles and excelsior fuel beds) and is compared with the predictions of both a very simple empirical model (Catchpole) and a detailed physical model (FireStar2D).

中文翻译：

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野火的对流-辐射传播模型

“Balbi 模型”是一种简化的表面火灾稳态物理传播模型，它考虑了来自燃烧燃料颗粒表面区域和火焰体的辐射传热。在这项工作中，提出了这种野火传播模型的全新版本。即使在目前的工作中，该模型仅限于实验室实验，但其目的是在操作条件下在现场更大规模地使用。该模型是根据辐射传播模型构建的，并添加了一个对流热传递项，这是由于热反应气体包撞击位于火焰底部的未燃烧燃料元件而产生的。燃料床内的火焰被视为文献中描述的“火指”。提出的模型是基于物理的，比实时更快且完全可预测，这意味着模型参数不会从一个实验到另一个实验发生变化。预测的传播速率应用于大量实验室实验（通过均质松针和精益求精的燃料床），并与非常简单的经验模型 (Catchpole) 和详细物理模型 (FireStar2D) 的预测进行比较。