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研究报告

摘要：为获得一定尺寸、浓度、流量范围的稳定的黑碳气溶胶用于实验研究，设计了一种基于倒置式共流扩散火焰燃烧的黑碳气溶胶发生器；与文献已有设计相比，本设计改进了流量控制、点火操作，并采用催化氧化器去除有机物.本研究设计的发生器产生的颗粒物总数浓度在3 h内的偏差为8.33%，峰值粒径的浓度偏差小于10%，能够产生稳定的黑碳气溶胶，且产生的黑碳气溶胶粒径主要集中在30~300 nm；当燃烧当量比φ由0.60上升至0.90时，黑碳气溶胶数浓度由1.31×10⁷#·cm^-3增大到8.16×10⁷#·cm^-3，峰值粒径从109.4 nm增大到145.9 nm；黑碳气溶胶尺寸、浓度有较大的变动范围.采用催化氧化器能够有效去除不同黑碳气溶胶浓度范围内的有机物质，获得有机物含量低于3%的黑碳气溶胶，且催化氧化器能在6 L·min^-1流量范围下工作.产生的黑碳气溶胶以链状结构的聚合体为主，分形维数为2.01，该聚合体主要由球型小单体聚集组成，黑碳气溶胶的吸收波长指数为1.04.

Abstract：A black carbon aerosol generator was designed based on inverted co-flow diffusion flame combustion. Stable black carbon aerosols with a certain size, concentration and flow rate range could be obtained with this generator for experimental studies. Compared with existing ones, this design has improved the flow rate control and ignition operation. Moreover, a catalytic oxidizer was used to remove organic matter. The size of black carbon aerosol is mainly between 30 nm and 300 nm. The standard deviation coefficient of the particle concentration produced by the generator in 3 hours is 8.33%, and the deviation of particle concentrations within peak size range is less than 10%. As the combustion equivalent ratio φ increased from 0.60 to 0.90, the concentration of black carbon aerosol rose from 1.31×10⁷ #·cm^-3 to 8.16×10⁷ #·cm^-3, and the size peak shifted from 109.4 nm to 145.9 nm. The size and concentration of black carbon aerosol have a wide range of variation. For black carbon aerosol of varied concentrations, the catalytic oxidizer could effectively reduce the percentage of organic substances in black carbon aerosol to below 3%, while the catalytic stripper worked at a flow rate of below 6 L·min^-1.The black carbon aerosols obtained were mainly chain-like aggregates, and their fractal dimension was 2.01. The absorption angstrom exponent of black carbon aerosol was 1.04.

Key words：black carbon aerosol generator performance test stable size distribution chain-like aggregates