Reducing Multiple Charging of Submicron Aerosols in a Corona Diffusion Charger
Reducing Multiple Charging of Submicron Aerosols in a Corona Diffusion Charger
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减少电晕扩散充电器中亚微米气溶胶的多次充电
DOI：
10.1080/02786820701787969
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发表时间：
2008
影响因子：
5.2
通讯作者：
A. Schmidt
中科院分区：
文献类型：
--
作者：
María M. Vivas;E. Hontañón;A. Schmidt
现有的电晕扩散充电器（Büscher 等人，1994）经过优化，以减少亚微米颗粒的多次充电。将正零矩形波电压施加到内部电极，并且通过改变脉冲电压的占空比（即，施加到电极的电压为正的时间的比例）来控制充电区域中的离子浓度。针对粒径在 50 至 250 nm 范围内、数量浓度低于 10 5 cm−3 的单分散气溶胶，对电晕充电器的性能进行了实验和理论评估。确定了+4.5 kV 和+5 V 的最佳电晕电压和脉冲电压值。大约 10% 的占空比会产生与双极充电器中的带正电粒子相当的多个充电水平，并且单带电粒子的比例更高。通过进一步降低占空比可以减少多次充电。当使用电晕离子发生器对多分散气溶胶进行充电时，必须根据气溶胶颗粒数浓度来调整操作电晕电压和脉冲电压值。电晕充电器适用于通过微分迁移率分析 (DMA) 对亚微米颗粒进行尺寸选择。
An existing corona diffusion charger (Büscher et al. 1994) is optimized in order to reduce multiple charging of submicron particles. A positive-zero rectangular wave voltage is applied to the inner electrode and the ion concentration in the charging region is controlled by varying the duty cycle of the pulse voltage, i.e., the fraction of time during which the voltage applied to the electrode is positive. The performance of the corona charger is assessed experimentally and theoretically for monodisperse aerosols with particle sizes in the range of 50 to 250 nm and number concentrations below 10 5 cm−3. Optimal corona voltage and pulse voltage values of +4.5 kV and +5 V are identified. A duty cycle about 10% resulted in multiple charging levels comparable to positively charged particles in bipolar chargers, with higher fractions of singly charged particles. Multiple charging can be lowered by reducing further the duty cycle. When using the corona ionizer for charging of polydisperse aerosols, operational corona voltage and pulse voltage values must be adjusted in dependency of the aerosol particle number concentration. The corona charger is suitable for size selection of submicron particles by differential mobility analysis (DMA).