声波灭火微观机理及其诱导下的热-流-声多场耦合特性研究

Environmental pollution and inducing of secondary disasters have been always challenges of the conventional fire extinguishing technologies for fires happened at special places such as petrochemical Enterprise, museum, computer laboratory, space capsule etc. Compared with conventional fire extinguishing technologies, the new proposed acoustic fire extinguishing technique has distinct advantages including extensive application, green environmental protection etc. The most important is that this technique does not induce any secondary disasters. However, the extinguishing mechanism of this technique has not been revealed. Thus, parameters for guarantee the effective and efficient fire extinguish have not been optimized. In this proposed project, high-speed camera, oscillation spectrum, PIV, and PLIF are employed to characterize the structural properties of the flame and propagation property of the acoustic wave. Further, frontal structure, vortex characteristics, and temperature field of the flame and concentration distributions of OH· and HCO· are comprehensively analyzed to reveal extinguishing mechanism of the acoustic wave. According to acoustic principles, an acoustic fire extinguishing experimental system was designed and set up. Extinguishing characteristics of the flame under acoustic wave are investigated on the basis of the self-designed system. Then, the optimal parameters and limitations of the acoustic wave for fire extinguishing are ascertained. Based on the similarity simulation experiment system of tunnel, numerical simulation is combined with the experimental tests to study coupling characteristic of thermal field, air-flow field, and sound field of the fire. The extinguishing effect of the acoustic wave under the condition of strong reflection was tested as well. Achievements of this project will provide scientific basis and theoretical guidelines for development and application of the acoustic fire extinguishing technique.

常规灭火技术在扑救石化企业、博物馆、计算机房、太空舱等特殊场所火灾的过程中，往往容易造成环境污染或带来次生损失，新近提出的声波灭火技术具有适用性强、本质绿色环保、不会诱发次生灾害等优点。针对该技术当前存在的灭火机理不清、最佳灭火参数不明等问题，本项目拟采用高速摄像机、纹影仪、PIV和PLIF等先进的实验仪器，在对火焰结构特征和声波传播特性进行测试的基础上，重点研究声波作用下火焰锋面结构、漩涡特征、温度场和自由基（OH·、HCO·等）浓度分布等火焰信息的变化规律，旨在揭示声波灭火的微观作用机理；通过自制的声波灭火实验系统，研究声波作用下火焰的熄灭特性，进而确定声波灭火的最优参数和极限参数；基于隧道相似模拟实验系统，采用数值模拟和实验测试相结合的方法研究火场热-流-声多场耦合作用规律，并对强反射条件下声波的灭火特性进行测试。项目研究成果可以为声波灭火技术的开发和应用提供科学依据和理论指导。

火灾每年造成大量的人员伤亡和财产损失，常规灭火技术在扑救石化企业、博物馆、计算机房、太空舱等特殊场所火灾的过程中，存在容易造成环境污染、带来次生损失、产品易过期失效等缺点。本研究提出的声波灭火技术具有适用性强、本质绿色环保、不会诱发次生灾害等优点。针对该技术当前存在的灭火机理不清、最佳灭火参数不明等问题，项目测试了火焰关键特性参数（如形态、倾角、高度、温度等）的时空演变特征，阐明了火焰锋面结构参数的周期性变化规律，揭示了火焰振荡频率与油盘直径之间的关联机制；自行研发并搭建了声波灭火试验台，采用声波探测设备测试了声波灭火系统的声压的是时域变化和空间衰减规律；建立了声波灭火的数学模型，阐明了声波灭火过程中的卡尔文-亥姆霍兹不稳定现象，揭示了声波灭火的微观作用机理，并结合数学模型和实验测试结果确定了声波灭火的最优频率和极限灭火距离等关键参数；最终通过实验测试和数值模拟揭示了声波灭火过程中的热-流-声多场耦合特征。项目研究成果能够为优化声波灭火装置、促进声波灭火系统的工业化应用奠定基础，带来潜在的经济和社会效益。