Abstract Quasi-steady behavior of a flowing propane/air mixture ignited by a surface heated at a constant power was investigated as a first step in assessing the physical risk of alternative clean energy. A series of experiments was carried out in which flowing propane was exposed to a heated surface at various supplied voltages and flow velocities. From the experimental results, the following findings were obtained: (1) ignition initiated from the bottom of the heated surface, and a flame first propagated on the downstream side of the heated surface; (2) the existence of the critical heat flux to ignite the flowing mixture was found, which was a major difference between ignition by a constant-temperature, hot surface and that by a constant-heat-flux, heated surface; (3) the limit of ignition temperature was expressed as a function of flow velocity, and the size of heated surface, yielding a curve which converges to a critical value of ignition temperature. The experimentally-measured dependence of the critical heat flux and ignition temperature on the flow velocity was consistent with the prediction of theoretical analysis conducted in this study.

中文翻译：

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受热表面点燃流动丙烷/空气混合物的准稳态特性

摘要 作为评估替代清洁能源的物理风险的第一步，研究了由以恒定功率加热的表面点燃的流动丙烷/空气混合物的准稳态行为。进行了一系列实验，其中流动的丙烷以不同的供电电压和流速暴露于加热表面。实验结果表明：（1）着火从受热面底部开始，火焰首先在受热面下游传播；(2) 发现了点燃流动混合物的临界热通量的存在，这是恒温热面点火与恒热通量加热面点火的主要区别；(3) 着火温度的极限被表示为流速和受热面尺寸的函数，产生一条收敛到着火温度临界值的曲线。实验测量的临界热通量和点火温度对流速的依赖性与本研究中进行的理论分析的预测一致。