Abstract Experiments were conducted to quantify the magnitude and contribution of flame heat feedback and char oxidation on the burning of timber. Using both oxidative and inert environments (air and nitrogen) a methodology was developed to determine the individual contribution of flame and char oxidation. The rate of pyrolysis, expressed through the mass loss rate, was used to calculate the individual contributions of flame heat flux and char oxidation. The process of timber combustion was divided into an initial transient regime and a quasi-steady regime. Equivalent heat flux contributions were calculated using the mass loss rate and the heat of pyrolysis. At the peak mass loss rate, the flame heat feedback contributed up to 60% of the total mass loss rate. The total contribution of flame radiation and char oxidation was determined to be constant with incident applied heat flux at quasi-steady state (2.5–2.9 kW/m2). However, the contribution towards peak mass loss rate decreases at higher incident heat fluxes. Flame heat fluxes were calculated between 19.9 and 20.6 kW/m2 at low external heat fluxes (20 and 25 kW/m2). The resulting heat flux contributions agree with previous studies, with particularly good agreement at lower heat fluxes.

中文翻译：

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炭氧化和火焰热反馈对木材质量损失率的时间依赖性贡献

摘要 进行了实验以量化火焰热反馈和炭氧化对木材燃烧的大小和贡献。使用氧化和惰性环境（空气和氮气）开发了一种方法来确定火焰和炭氧化的单独贡献。通过质量损失率表示的热解率用于计算火焰热通量和炭氧化的单独贡献。木材燃烧过程分为初始瞬态和准稳态。使用质量损失率和热解热计算等效热通量贡献。在峰值质量损失率下，火焰热反馈贡献了总质量损失率的 60%。在准稳态 (2.5-2.9 kW/m2) 下，火焰辐射和炭氧化的总贡献被确定为恒定的入射热通量。然而，在更高的入射热通量下，对峰值质量损失率的贡献降低。在低外部热通量（20 和 25 kW/m2）下计算的火焰热通量在 19.9 和 20.6 kW/m2 之间。由此产生的热通量贡献与先前的研究一致，在较低的热通量下特别好。