 |
| Titel |
Numerical simulations of mixing conditions and aerosol dynamics in the CERN CLOUD chamber |
| VerfasserIn |
J. Voigtländer, J. Duplissy, L. Rondo, A. Kürten, F. Stratmann |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 4 ; Nr. 12, no. 4 (2012-02-29), S.2205-2214 |
| Datensatznummer |
250010747
|
| Publikation (Nr.) |
 copernicus.org/acp-12-2205-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| 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. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|