散水による可燃物の熱分解および着火の遅延効果に関する研究

摘要

本研究では、散水中においても表面に水膜が形成されず可燃物が 熱分解または着火に至る条件に主眼を置き、散水による可燃物の熱 分解および着火の遅延効果を把握することを目的として、以下に示す2種類の試験体を用いた実験を実施した。また、それらの実験結 果および既存の熱着火理論を用いて、散水による受熱低減効果を考 慮したみかけの入射熱流束qnet,appと可燃物の熱分解時間および着火 時間の関係について整理した。%A series of experiments using electric heater and water application was carried out to comprehend the effect of delay of pyrolysis and ignition owing to water supplying. Main parameters of the experiments are radiative heat flux and water delivered density onto the specimen surface. As the results of experiments, time to pyrolysis and ignition increased as increasing water delivered density at each external heat flux. According to the results of comparison of external heat flux and inverse square root of time to pyrolysis 1/ √tp, time to pyrolysis with water application can be estimated by using correlation between external heat flux and time to pyrolysis without water application when incident heat flux with water is regarded as the external heat flux minus sensible heat and latent heat of water (qex-w·L_w). On the other hand, calculated value of time to ignition by using same method is shorter than actual value.