Numerical simulations of mixing conditions and aerosol dynamics in the CERN CLOUD chamber

To study the effect of galactic cosmic rays on aerosols and clouds, the Cosmics Leaving OUtdoor Droplets (CLOUD) project was established. Experiments are carried out at a 26.1 m3 tank at CERN (Switzerland). In the experi
To study the effect of galactic cosmic rays on aerosols and clouds, the Cosmics Leaving OUtdoor Droplets (CLOUD) project was established. Experiments are carried out at a 26.1 m3 tank at CERN (Switzerland). In the experiments, the effect of ionizing radiation on H2SO4 particle formation and growth is investigated. To evaluate the experimental configuration, the experiment was simulated using a coupled multidimensional computational fluid dynamics (CFD) – particle model. In the model the coupled fields of gas/vapor species, temperature, flow velocity and particle properties were computed to investigate mixing state and mixing times of the CLOUD tank's contents. Simulation results show that a 1-fan configuration, as used in first experiments, may not be sufficient to ensure a homogeneously mixed chamber. To mix the tank properly, two fans and sufficiently high fan speeds are necessary. The 1/e response times for instantaneous changes of wall temperature and saturation ratio were found to be in the order of few minutes. Particle nucleation and growth was also simulated and particle number size distribution properties of the freshly nucleated particles (particle number, mean size, standard deviation of the assumed log-normal distribution) were found to be distributed over the tank's volume similar to the gas species.
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Metadaten
Author:Jens Voigtländer, Jonathan Duplissy, Linda Rondo, Andreas Kürten, Frank Stratmann
URN:urn:nbn:de:hebis:30:3-252263
URL:http://www.atmos-chem-phys.net/12/2205/2012/acp-12-2205-2012.html
DOI:http://dx.doi.org/doi:10.5194/acp-12-2205-2012
ISSN:1680-7324
Parent Title (English):Atmospheric chemistry and physics
Publisher:European Geosciences Union
Place of publication:Katlenburg-Lindau [u.a.]
Document Type:Article
Language:English
Date of Publication (online):2012/02/29
Date of first Publication:2012/02/29
Publishing Institution:Univ.-Bibliothek Frankfurt am Main
Release Date:2012/06/18
Volume:12
Pagenumber:10
First Page:2205
Last Page:2214
Institutes:Geowissenschaften
Dewey Decimal Classification:550 Geowissenschaften
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 3.0

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