基于协同效应的气-液复合介质用于民用飞机货舱灭火的研究

With the approaching of limited date for the aviation industry to transition to the use of non-halon agents, there is an increasing concern for aircraft manufacturers to find an ideal candidate. Clean chemical gas and water mist are two typical halon replacement candidates. For their different physicochemical properties and extinguishing mechanisms, they show different advantages and shortcomings when used alone in cargo compartments. The project aims to combine chemical gas and water mist for fire suppression in the cargo compartment of civil aircraft, by taking advantages of the individuals to achieve synergistic effects. First, fire extinction performance of the composite agents will be evaluated by a standard cup burner method. Optimal gas-liquid combination will be found from investigations on the varying trend of the synergetic effects. Then the dynamic behaviors and spatial concentration distribution of the synergetic suppressants in a simulated cargo compartment will be identified by a series of advanced instruments, such as particle imaging velocimetry (PIV) and planar laser induced fluorescence (PLIF), etc. Based on optical diagnosis and computer fluid dynamics (CFD) simulation, a theoretic model will be established for predicting the motion and distribution of composite suppressants in a confined space. Furthermore, total flooding fire extinguishment tests would be conducted based on minimum performance standard (MPS) for aircraft cargo compartment halon replacement fire suppression systems. Consequently, optimal quantitative conditions will be determined for the application of gas-liquid composite agents in the fire suppression of cargo compartments. The results are expected to provide important experimental data and theoretical directions for halon replacement fire suppression in the cargo compartment of civil aircraft.

随着民用飞机哈龙灭火剂替代期限的临近，迫切需要寻找理想的替代物。洁净化学气体和细水雾是两种典型的哈龙替代灭火介质，但它们的理化特性和灭火机制不同，用于飞机货舱灭火时各有优势和局限。本项目拟将洁净化学气体和细水雾合理联用，以发挥协同灭火效应，实现优势互补，探索其作为飞机货舱哈龙替代灭火剂的可行性。首先通过杯式燃烧器实验，系统研究复合介质协同灭火效应变化规律，确定气液两相最佳组合方式；再根据飞机货舱原型尺寸构建模拟空间，利用粒子图像测速仪（PIV）和平面激光诱导荧光（PLIF）等先进的测试手段，揭示复合介质的运动行为和浓度分布特征，并结合计算流体力学模拟，建立复合介质运动分布理论预测模型；最后，基于飞机货舱哈龙替代灭火系统最低性能标准（MPS），开展全淹没灭火模拟实验，明确气-液复合介质用于货舱灭火的定量条件。研究结果将为飞机货舱哈龙灭火系统的替代提供重要的实验数据和理论指导。

针对民用飞机货舱对新型哈龙替代灭火剂的迫切需求，本项目旨在探索洁净化学气体和细水雾所组成的气-液复合介质应用于飞机货舱灭火的可行性, 研究其中的基础科学问题：（1）以细水雾分别与氮气、五氟乙烷、溴氟丙烯和全氟己酮4种洁净气体所组成的复合介质为研究对象，基于杯式燃烧器实验方法，开展了气-液复合介质灭火性能表征，发现不同种类和比例的气、液介质复合灭火时，分别存在加和、协同和拮抗作用，明确了各复合介质灭火效应变化规律；（2）采用激光诱导荧光技术和粒子图像测速技术，探测了复合介质作用下火焰中OH·自由基的浓度分布和细水雾运动流场，发现了化学灭火剂和物理灭火剂作用下OH·自由基浓度及分布位置的显著区别，掌握了气-液复合介质协同灭火的物理化学特征；（3）通过全尺寸灭火剂喷射实验，结合阴影法和示踪激光诱导荧光技术，研究了洁净化学气体在输运管道中的流动特性、出口喷雾的形态及其空间浓度分布规律，观测到不同热物理特性的灭火剂喷雾中分别存在马赫盘和分散液滴，揭示了喷射流量、喷嘴位置及混合时间等因素对灭火剂空间浓度分布均匀性的影响；（4）基于缩尺寸模拟灭火实验，验证了复合介质用于受限空间全淹没灭火的效能，确定了气-液复合灭火的定量优化条件。研究结果可以为飞机货舱灭火系统的哈龙替代提供实验验证和理论指导，促进复合灭火技术的发展。