基于光声气体滤波的早期火灾烟气测量方法

GFC Photoacoustic Measurement Method for Fire Products

火灾烟气中气体和烟雾浓度测量对火灾研究有着重要意义。本文提出一种利用光声技术同时在线测量CO浓度和烟雾消光的非接触式方法。根据气体滤波和粒子散射原理,采用两个光声腔分别作为CO测量腔和烟雾参比腔,在其与光源之间的开放路径中进行火灾产物的测量,通过测量两个光声腔信号,依据信号变化量计算CO浓度和烟雾消光。基于标准火的实验证明该方法可以实现烟雾颗粒和CO气体的复合测量。

Sensitive detection and measurement of evolved gas and smoke are always the important demand in fire research. This paper presented a new non-contact method to meter CO concentration and smoke optical density simultaneously and online based on photoacoustic technology. According to gas filter theory and particle light scattering theory, fire products, including gaseous components and smoke particles, were metered in the measuring path between the infrared light source and the photoacoustic cells. Two photoacoustic cells including one CO gas cell and one reference gas cell were used to work as gas filters. Their photoacoustic signal attenuation during the measurement indicated the light extinction caused by CO absorption and smoke particles extinction respectively. Thus CO concentration and smoke optical density can be obtained by processing the photoacoustic signal using the model established in the paper. Experiments of standard test fires show that this method can realized for the compound measurement of smoke particles and CO gas.