建筑火灾烟气环境对太赫兹波传播特性的影响研究

When a terahertz wave propagates in the fire scenario, coupling the influence of scattering and absorbtion of smoke particles, the propagation characteristics present a unique form. Thus, the study of terahertz wave propagation characteristics in fire scenario can obtain the inversion of fire environment which can support to solve the problem of poor visibility. The project research the absorption and scattering effect of the smoke particle while a terahertz pulse wave passes through, with the consideration of the smoke particle’s fractal condensation structure. The scattering model will be built to reveal the influence of smoke structure to the smoke scattering. Based on considering the coagulation effect, the smoke particle size distribution in the building fire scenario was studied. Combined with the smoke scattering model, to reveal the relationship between the terahertz wave intensity and pulse width with the smoke density and the smoke particle size distribution. The smoke spread rule in a typical room-corridor space was studied to analyze the non-uniform structure of the smoke. With the relationship between the terahertz wave intensity and pulse width with the smoke density and the smoke particle size distribution, the terahertz pulse wave propagation model in the building fire scenario was built and the fire environment inversion algorithm is put forward. The research result can support to solve the low visibility problem which causes the firefighters cannot see clearly in the smoke scenario giving rise to the casualties, the tardiness of evacuation and rescue.

太赫兹波在火场烟气环境中传播时，受烟颗粒的散射和吸收作用，其传播特性呈现特有的表现形式。对太赫兹波传播特性的研究可为解决当前火场低能见度问题提供重要的支持。本项目结合烟颗粒独特的分形凝聚体结构，研究烟颗粒对太赫兹脉冲波的散射、吸收作用，建立烟颗粒对太赫兹脉冲波的散射模型，揭示颗粒形态特征对烟颗粒散射的影响规律；基于烟颗粒凝并效应，研究建筑火灾烟颗粒粒径分布规律，结合烟颗粒对太赫兹脉冲波的散射模型，揭示太赫兹脉冲波强度等参量与烟颗粒粒径分布的变化关系；研究建筑内典型房间-走廊结构的烟气迁移规律，揭示烟气的非均匀流场结构，结合太赫兹脉冲波强度等随粒径分布的变化关系，建立建筑火灾烟气环境太赫兹脉冲波传播模型，并以此提出火场环境反演算法。为解决当前火场低能见度导致消防人员无法辨识火场环境引发的伤亡、火场搜救缓慢等问题提供必要的理论支持。

火场环境成像技术已成为火灾探测领域的重要技术之一，现有的成像检测设备在低能见度火场环境下受烟气环境影响较大。本项目拟将太赫兹波成像检测技术应用于火场环境成像检测中，研究太赫兹波在火灾烟气环境中的传输特性。主要研究内容包括：烟颗粒的形貌特征、粒径对太赫兹波传输特性的影响，重点研究不同烟气环境下，太赫兹波衰减特性随烟颗粒粒径、烟颗粒浓度的变化规律。.（1）以烟颗粒粒径与太赫兹波波长为变化量分析，基于烟颗粒独特的分形凝聚体结构，通过理论分析和数值计算，结果表明：太赫兹波传输的衰减会随烟颗粒粒径的增大而增大，会随太赫兹入射波长的增大而减小；.（2）在分析烟颗粒对太赫兹波传输影响的基础上，通过多散射辐射传输模型，采用离散纵标法，模拟计算太赫兹波在烟颗粒群中的传输特性，分析了不同波长太赫兹波、不同烟颗粒粒径、不同烟气浓度条件下的传输特性，研究了太赫兹波与烟气环境之间的变化关系；.（3）搭建了均匀、非均匀烟气环境实验平台，以不同的实验燃料和烟气浓度控制为变化关系，对烟气环境下太赫兹波传播特性进行了实验验证，实验结果与理论结果基本吻合；.（4）基于以上研究成果，研制了结合太赫兹波检测与光电感烟的火灾感烟探测器，相较于传统的火灾感烟探测器，实现了光电感烟和太赫兹波检测双重探测的效果。