基于不对称比的火灾烟雾探测器散射角优化

Optimization of scattering angle for fire smoke detectors based on asymmetry ratio

为提升基于不对称比的火灾烟雾探测器的性能,优化散射角,通过对火灾烟雾粒径信息的收集,建立光散射物理模型,再采用离散偶极子近似(DDA)方法,计算一定粒径分布火灾烟雾的散射光强角分布,探讨颗粒形貌和尺寸参数对于散射特征的影响。计算结果表明:散射光强随观察角的增加在整体上呈现先下降后上升的趋势,散射光强最小值对应的角度随尺寸参数变化;基于不对称比的烟雾探测器散射角的优化设计关键在于后向散射角的选取,当尺寸参数较小时,后向散射角应选择110°,当尺寸参数较大时,后向散射角应选择135°。

In order to improve performance of smoke detectors based on asymmetric ratio,scattering angle was optimized,and a light scattering physical model was established based on collected particle size information of fire smoke.Then,angular distribution of scattered light intensity was calculated with a certain particle size distribution by using DDA method,and influence of particle morphology and size parameter on scattering characteristics was discussed.The results show that scattered light intensity decreases first and then rises as observation angle increases,and the angle corresponding to the minimum intensity value changes withe size parameter.The key to optimize scattering angle design of smoke detectors based on asymmetry ratio lies in the selection of back-scattering angle which should be 110°when size parameter is small and 135°when the parameter is large.