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为探索木材在热流变化时的着火特点并提出着火判据,通过试验研究了木材在线性增长热流条件下的自发着火性能,测定了泡桐、椿木、榆木和刺槐4种木材的点燃时间、木材表面的入射热流以及试样内部的温度。结果表明,当热流增长率大于等于0.199kW/(m~2·s)时,试验的所有木材均可以被点燃,点燃这些木材的临界热流增长率介于0.065～0.103 kW/(m~2·s)。建立了木材着火的计算模型,计算得出木材自发着火时的表面温度约为500℃。根据试验和计算的结果提出了结合表面温度和临界热流增长率的木材自发着火复合判据。
In order to explore the characteristics of fire and the ignition criterion of wood when the heat flow changes, the spontaneous ignition performance of wood under the condition of the linear growth heat flux is studied through experiments. The ignition time of four woods including paulownia, pumila, elm and black locust, The incident heat flow on the wood surface and the temperature inside the sample. The results show that all of the tested woods can be ignited when the rate of increase of heat flux is greater than or equal to 0.199kW / (m ~ 2 · s), and the critical heat flux for igniting these woods increases from 0.065 to 0.103 kW / (m 2 · s) s). The calculation model of wood fire was established, and the surface temperature of wood spontaneous fire was calculated to be about 500 ℃. According to the results of experiments and calculations, a composite criterion of spontaneous combustion of wood combined with the growth rate of surface temperature and critical heat flux is proposed.