一种新型软X射线气溶胶荷电器的开发与评测

Development and Evaluation of a New Soft X-Ray Aerosol Charger

现有荷电器对1~3 nm气溶胶的通过效率和荷电效率都较低。研发了一种新型软X射线气溶胶双极荷电器,通过结构设计的改进极大地提高了3 nm以下气溶胶的通过效率,同时该荷电器对不同粒径气溶胶的本征荷电效率仍与现有荷电器相近。实验室评测结果表明:在1 L·min-1流量下,新型荷电器对3 nm以下不同粒径气溶胶的通过效率与TSI 3088软X射线荷电器相比可提高175%~300%;在2.5 L·min-1流量下,可提高115%~173%。同时,新型荷电器对10~40 nm及3 nm以下气溶胶的本征荷电效率与目前广泛使用的Fuchs稳态理论近似公式计算得出的荷电效率及其他类似荷电器的实测荷电效率基本吻合。相对于现有的商业荷电器,该新型荷电器对3 nm以下气溶胶有着更高的表观荷电效率,具有潜在的应用价值。

Currently most of the aerosol chargers have poor penetration and charging efficiencies for 1~3 nm aerosols. A new soft X-ray aerosol charger is developed and evaluated. While maintaining similar intrinsic charging efficiency to the other chargers, its penetration efficiency is significantly increased through the improvement of the structure design. Laboratory evaluations show that, compared with commercialized TSI 3088 soft X-ray charger, the penetration efficiencies of the new developed charger for sub-3 nm aerosols have been increased by 175%~300%and 115%~173% under 1.0 and 2.5 L·min-1 flow rates, respectively. Meanwhile, the intrinsic charging efficiencies of the new charger for 10~40 nm and sub-3 nm aerosols is basically consistent with the intrinsic charging efficiencies estimated by a well-accepted Fuchs steady state approximation formula and those of the other similar aerosol chargers. Therefore, compared with the existing commercial chargers, the new developed charger is beneficial for its higher extrinsic charging efficiency for sub-3 nm aerosols, which indicates its potential application value.