Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Acoustic separation of sub-micron particles in gases
KTH, School of Engineering Sciences (SCI), Mechanics.
KTH, School of Engineering Sciences (SCI), Mechanics.ORCID iD: 0000-0002-4171-5091
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.ORCID iD: 0000-0002-6326-4084
2013 (English)In: Proceedings of Meetings on Acoustics: Volume 19, Issue 1, June 2013, Acoustical Society of America (ASA), 2013, 045020- p.Conference paper, Published paper (Refereed)
Abstract [en]

In several areas of science and technology there is a strong need for concentrating, separating and sorting small particles suspended in gaseous flows. Acoustic fields can be used to accomplish this task, an approach extensively used in liquid phase microfluidics that has great potential for aerosol treatment. This paper presents an experimental investigation of acoustophoresis for very small particles in gases, with sizes ranging from tens to hundreds of nanometers. The phenomenon is studied in a rectangular channel with variable height in which a standing acoustic field is created by a broadband electrostatic transducer operated in the 50-100 kHz range. Downstream of the separation channel, the flow is separated into enriched and depleted streams with adjustable slits for analysis. The particle number density and size distribution is measured with a Scanning Mobility Particle Sizer (SMPS) as a function of position in the standing wave pattern. From these measurements, the separation efficiency is determined as a function of the particle size and the amplitude of the acoustic field. For the very small particles used here, this yields novel information on the magnitude of acoustophoretic forces in the transition and molecular flow regimes.

Place, publisher, year, edition, pages
Acoustical Society of America (ASA), 2013. 045020- p.
Series
Proceedings of Meetings on Acoustics, ISSN 1939-800X ; 19
Keyword [en]
Electrostatic transducers, Experimental investigations, Particle number density, Scanning mobility particle sizer, Science and Technology, Separation efficiency, Standing wave patterns, Sub-micron particles
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:kth:diva-134176DOI: 10.1121/1.4800812Scopus ID: 2-s2.0-84878982914OAI: oai:DiVA.org:kth-134176DiVA: diva2:665125
Conference
21st International Congress on Acoustics, ICA 2013 - 165th Meeting of the Acoustical Society of America; Montreal, QC; Canada; 2 June 2013 through 7 June 2013
Note

QC 20131119

Available from: 2013-11-19 Created: 2013-11-18 Last updated: 2016-11-25Bibliographically approved
In thesis
1. Acoustic separation and electrostatic sampling of submicron particles suspended in air
Open this publication in new window or tab >>Acoustic separation and electrostatic sampling of submicron particles suspended in air
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

We investigate experimentally the effects of acoustic forces on submicron aerosol in a channel flow. This technique can potentially overcome some of the limitations of conventional separation systems and provide advanced manipulation capabilities such as sorting according to size or density. The theoretical framework for acoustophoresis at such small length scales where molecular effects are expected to be significant is still incomplete and in need of experimental validation. The main objectives of this thesis are to identify the physical limitations and capabilities of acoustophoretic manipulation for submicron aerosol particles.

Two sets of experiments were carried out: first, qualitative results revealed that acoustic manipulation is possible for submicron particles in air and that the acoustic force follows the trend expected by theoretical models developed for particles in inviscid fluids. The acoustic force on submicron particles was estimated in a second set of measurements performed with quantitative diagnostic tools. Comparison of these results with available theoretical models for the acoustic radiation forces demonstrates that for such small particles additional forces have to be considered. At submicron length scales, the magnitude of the forces observed is orders of magnitude higher than the predictions from the inviscid theory.

One potential application for acoustophoresis is specifically investigated in this thesis: assist electrostatic precipitation (ESP) samplers to target very small aerosols, such as those carrying airborne viruses. To identify the shortcomings of ESP samplers that acoustophoresis should overcome, two ESP designs have been investigated to quantify capture efficiency as a function of the particle size and of the air velocity in a wind tunnel. The results reveal that both designs have limitations when it comes to sampling submicron aerosol particles. When exposed to polydispersed suspensions they behave as low-pass filters.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. 77 p.
Series
TRITA-MEK, ISSN 0348-467X
Keyword
Acoustic, separation, acoustophoresis
National Category
Fluid Mechanics and Acoustics
Research subject
Engineering Mechanics
Identifiers
urn:nbn:se:kth:diva-196857 (URN)978-91-7729-221-0 (ISBN)
Public defence
2016-12-16, D3, Lindstedsvägen 5, Stockholm, 10:15 (English)
Opponent
Supervisors
Note

QC 20161125

Available from: 2016-11-25 Created: 2016-11-24 Last updated: 2016-11-25Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Engvall, Klas

Search in DiVA

By author/editor
Robert, EtienneImani Jajarmi, RaminEngvall, Klas
By organisation
MechanicsChemical Technology
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 54 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf