Abstract A systematic visualisation system that can image the visible flame, invisible hot gas and the wood surface temperature, was applied to study self-sustained fire propagation in a wood rod at different inclination angles. It was found that the burned wood rods at positive inclination angles presented longer burning lifetimes and charring lengths than those at negative and horizontal angles. Three physical phenomena were found to determine the fire sustaining and propagation: 1. Underneath hot gas layer; 2. Flame attachment phenomenon; 3. Impact point of piloted imping heat flux. Longer underneath hot flow was observed at positive inclination angles. The underneath hot gas flow could preheat the adjacent wood making them more readily for fire propagation. The flame attachment length and flame tilt angle had been investigated and quantified with enhanced thermal images. It was found that the flame is more prone to attach to the rod at positive angles. The impact point of piloted impinging heat flux was analysed by multiple imaging systems. Higher positive inclinations mean that a larger part of the rod is contacting with the impinging heat flux. The new insights gained are beneficial for fire safety in construction especially for the fire propagation at early stage.

中文翻译：

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多光谱和纹影可视化预热对斜木火蔓延的影响

摘要 一个系统的可视化系统，可以对可见火焰、不可见热气和木材表面温度进行成像，用于研究不同倾斜角度的木杆自持火蔓延。结果表明，正倾角燃烧的木杆比负倾角和水平倾角的燃烧寿命和炭化长度更长。发现了三种物理现象来确定火的持续性和蔓延性： 1. 在热气层下方；2.火焰附着现象；3.先导冲击热流的冲击点。在正倾角下观察到更长的下方热流。下面的热气流可以预热相邻的木材，使它们更容易火势蔓延。火焰附着长度和火焰倾斜角已经通过增强的热图像进行了研究和量化。发现火焰更容易以正角度附着在棒上。通过多个成像系统分析了先导撞击热通量的影响点。更高的正倾角意味着杆的较大部分与撞击热通量接触。获得的新见解有利于建筑消防安全，特别是早期火灾蔓延。