TY  - JOUR
A1  - Voigtländer, Jens
A1  - Duplissy, Jonathan
A1  - Stratmann, Frank
T1  - Numerical simulation of flow, H₂SO₄ cycle and new particle formation in the CERN CLOUD chamber
T2  - Atmospheric chemistry and physics. Discussions
N2  - To study the effect of galactic cosmic rays on aerosols and clouds, the Cosmic Leaving OUtdoor Droplets (CLOUD) project was established. Experiments are carried out at a 26 m3 tank at CERN (Switzerland). In the experiments, the effect of ionising particle radiation on H2SO4 particle formation and growth is investigated. To evaluate the experimental configuration, the experiment was simulated using a coupled multidimensional CFD – particle model (CLOUD-FPM). In the model the coupled fields of gas/vapour species, temperature, flow velocity and particle properties were computed to investigate the tank's mixing state and mixing times. Simulation results show that the mixing state of the tank's contents largely depends on the characteristics of the mixing fans and a 1-fan configuration, as used in first experiments, may not be sufficient to ensure a homogeneously mixed chamber. To mix the tank properly, 2 fans are necessary. The 1/e response times for instantaneous changes of wall temperature and saturation ratio inside the chamber 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 mixed over the tank's volume similar to the gas species.
Y1  - 2011
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/25225
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-252259
SN  - 1680-7375
SN  - 1680-7367
N1  - © Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License.
VL  - 11
SP  - 20013
EP  - 20049
PB  - European Geosciences Union
CY  - Katlenburg-Lindau
ER  -