科研之友
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摘要
In general, the aerosols mixed in air medium can be regularly manipulated by means of the interactions between the aerosols and the acoustic field. The manipulable properties of aerosols can be engineered through geometric parameter and acoustic resonance condition of the underlying device. The aerosols manipulated by modulated multiple acoustic wavepackets (MAWP) in acoustic resonance condition is proposed and demonstrated in this paper, whose application belongs to an efficient aerosol removal technique. The experimental results indicated that the removal efficiency of aerosols was mainly influenced by the different harmonic order. The technique and process proposed in this paper was feasible for industrial application. The MAWP is modulated by means of the synthetic standing wave field at the resonant frequency 1.268 kHz. The aerosol manipulation processes through MAWP consist of the aerosol shift, collision aggregation and deposition between the dot and the anti neck of a single wavepacket. As a visual inspection confirming standing wave, the processes may also be applied in modulating the MAWP simultaneously. The manipulation efficiency can be increased due to the increase of wavepacket amount under the same operating conditions. The acoustic radiation force causes shift and accumulation of aerosol in waveguide and the secondary radiation force enhances collision aggregation and deposition thereof. The initial number concentration of particles <2.5 mu m (resp. larger than 2.5 mu m) was about 517,488 1/cf(3) (resp. 51,918 1/cf(3)). Under the action of these forces, the aerosols in waveguide were aggregated and deposited onto the inner wall of waveguide. At the end of experiment, the final number concentration of particles <2.5 mu m (resp. larger than 2.5 mu m) is about 59,096 1/cf(3) (resp. 392 1/cf(3)). The PM2.5 content of aerosols used in experiment is about 91%. The removal coefficients are larger than 85%. The deposition stripe distribution shows the specific pattern associated with a wavepacket. The surface of the stripe particles is covered with the uniform small hollows (similar to 105.7-177.7 nm), and plenty of nanoscale particles (similar to 13.66-16.55 nm) are grown around the surface of small hollows. It may be possible to develop a new way for large scale and batch aerosol processing to apply to the prospective emission control of industrial aerosols.
- 出版日期2017-12
- 单位东南大学
