烟气流速对感烟火灾探测器性能的影响

INFLUENCE ON PERFORMANCE OF SMOKE FIRE DETECTORS BY VELOCITY

针对列车等存在高速气流的特殊场所 ,利用火灾探测器综合模拟实验平台 ,实验研究了光电感烟与离子感烟火灾探测器在不同风速条件下的工作性能。实验结果表明 :在以相同量的阴燃棉绳作为烟源条件下 ,光电感烟探测器随着周围气流速度的增大 ,其灵敏度急剧下降 ;而离子型感烟探测器的灵敏度受外界气流速度影响较小 ,在高速气流条件下依然保持较高的灵敏度 ,较适合在高速气流环境中工作。

The objective of this paper is to evaluate the performance of photoelectric and ionization smoke detectors in different smoke velocities through the Fire Emulator/Detector Evaluator(FE/DE) developed by the State Key Laboratory of Fire-prevention Science (SKLFS) recently. The present research provides some powerful experimental supports for the selection of smoke fire detectors in particular. To bring the research into a full success, a series of experiments has been done with the smoldering cottons as the smoke source, and with the velocities 0.5 m/s, 1.0 m/s, 1.5 m/s, 2.0 m/s, 2.5 m/s, 3.0 m/s, 3.5 m/s, 4.0 m/s, 4.5 m/s, 5.0 m/s and 5.5 m/s, respectively. The same amount of smoldering cottons has also been used in each experiment to ensure the changing parameter between these experiments to keep the air velocity around the smoke detectors. In this way, it is possible to clearly observe the different responses of photoelectric and ionization smoke detectors in different smoke velocities. The research results indicate that the sensitivity of the photoelectric smoke detector decreases sharply while the velocity around it keeps increasing. However, under the same condition, the sensitivity of the ionization smoke detector does not drop abruptly as the photoelectric detector remains at the same level. Therefore, the preliminary analysis proves that such a phenomenon is accounted with differences in smoke-sensing principles and smoke tunnels' structures between these two kinds of smoke fire detectors.