室内多因素条件下香烟颗粒粒谱动态分布特征

烟颗粒粒径分布和浓度变化是探测香烟阴燃火灾初期的重要参数,研究香烟阴燃过程烟颗粒粒谱分布对火灾探测具有指导意义。实验通过在室内有风条件下展开,研究风速、位置、时间、烟源等因素对烟颗粒的粒径分布和形成规律的影响。结果表明:1随着时间的推移,GMD(Geometric Mean Diameter,几何平均直径)变大,烟颗粒数量浓度增加,但粒谱分布逐渐趋于稳定。2风速对颗粒粒谱形成的影响较为复杂,随着风速的增加,气流扰动加剧,烟颗粒浓度增加,GMD有减小的变化趋势。3在不同的位置,有风条件下烟颗粒随着气流迁移,最终在壁面处进行积累,离烟源越远位置,沿着风速方向浓度和GMD均变大。4烟颗粒的初始浓度也影响烟颗粒粒谱分布和运动特征,烟源数量越多,初始浓度越大,形成的烟颗粒浓度和GMD越大。

Dynamic distribution characteristics of tobacco smoke particles under indoor conditions

Particle size and size variation are important parameters for detecting cigarette combustion process, smoke particle size distribution is of importance to study.In order to analyze the effect of wind speed, location, time and cigarette numbers on the size distribution and production law of the tobacco smoke particles, a set of experiment was carried out under multi-factor indoor conditions. Results show that : 1) With the increase of time, the Geometric Mean Diameter (GMD) and the concentration of number increase, but the particle distribution tends stable gradually. 2) The effect of wind speed on the particle spectrum is more complex, as the wind speed increases, the air flow disturbance intensifies, the particle concentration increase and GMD reduces. 3) In different locations, smoke particles move along wind flow, and finally accumulate near the wall. The concentration and GMD increase along wind direction in farther location away from the smoke source. 4) The initial concentration of smoke particles affects the smoke particle distribution and movement characteristics. Tobacco smoke particles concentration and GMD increase with the increasing initial concentration.