受限空间正庚烷油池火火焰脉动频率研究

利用光电二极管接收火焰辐射光强，将光信号转换为电信号的原理，研究了受限空间内正庚烷油池火的火焰强度和脉动频率随时间的变化规律。结果表明：在一定的时间内，随着正庚烷油池火点燃后，开始一段时间内，受限空间内氧气充足，油池火燃烧强度迅速增大，当达到一定时间和强度后，由于燃料减少，受限空间内氧气不足，火焰强度开始逐渐减弱；从实验中观察到油池火燃烧前期阶段，火焰并未有波动，当燃烧一段时间后，受限空间内供氧不足，需要外界提供氧气，火焰开始波动，火焰脉动频率迅速增大，最大值达到1.5 Hz 左右，火焰脉动频率与油盘直径的拟合结果为f=1.06 D- 0.5。通过利用低成本的光电二极管实现监测受限空间内油池火火焰脉动频率，有利于受限空间内火灾探测技术发展。

Study on flame pulsation frequency of n-heptane pool fire in enclosed space

By using the principle of photodiode receiving the radiant light intensity of flame and converting the optical signal into electrical signal, the change of flame intensity and pulsation frequency of n-heptane oil pool fire with time in confined space was studied. Results: Within a certain period of time, after the n-heptane oil tank fire was ignited, the combustion intensity of the oil tank fire increases rapidly due to the sufficient oxygen in the restricted space for a certain period of time. When it reaches a certain time and intensity, the flame intensity begins to weaken gradually due to the reduction of fuel and insufficient oxygen in the restricted space.It was observed from the experiment that in the early stage of oil tank fire combustion, the flame did not fluctuate. After burning for a period of time, the oxygen supply in the restricted space was insufficient, and the outside world needed to provide oxygen. The flame began to fluctuate, and the flame pulsation frequency increased rapidly, reaching a maximum of about 1.5 Hz, the fitting result of flame pulsation frequency and oil pan diameter is f=1.06D- 0.5. In this paper, the low cost photodiode is used to monitor the flame pulsation frequency of oil pool in restricted space, which is beneficial to the development of fire detection technology in restricted space.