高温热表面油料热着火过程的时变模型与实验

针对高温热表面油液蒸发和着火过程的时变特征,考虑这一过程中的对流传质传热,建立了热源作用下油液蒸发与着火理论模型,并通过"热图法"和"奇点分析"求解出控制体着火所需的热源最低温度。以正庚烷为研究对象,对高温热表面油液蒸发与着火过程进行了实验。理论分析与实验表明:油液着火所需的热源最低温度随时间变化较大,尤其在蒸发开始的前10min内,点火温度存在极值,具有明显的时变特征,油液热着火时变模型理论预测结果与实验结果吻合较好,对机舱防火、灭火实践具有一定的参考作用。

Time-dependent model and experiment on hot surfaceignition process of liquid fuel

Targeting on the time-dependent characteristics of the hot surface evaporation and the ignition process of liquid fuel, and considering the convective heat and mass transfer of this process, a heat and mass transport model and the hot surface ignition model of liquid fuel were built. Through thermal chart method and critical point analysis, the critical ignition temperature of the control volume was obtained. Set n-heptanes as experimental subjects, an experimental study on the hot surface ignition process of liquid fuel was carried out. The theoretical analysis and experimental results show that the minimum temperature of the heat source required for the ignition is greatly dependent on time. Especially in the first ten minutes of the evaporation process，the minimum ignition temperature reaches extremum. The calculation results of the thermal ignition model are hishly consistent with the experimental results, which shows the validity of the model. In a sense, the model can attribute to some enlightenment and guidance to the design of fire protection and fire fighting practice.