Characterization of a cyclone spray chamber for ICP spectrometry by computer simulation

Abstract

The aerosol transport and modification in a typical cyclone spray chamber for ICP spectrometry is simulated for the first time by computational fluid dynamics (CFD). Information that is not accessible experimentally can be gained, for example, about the droplet deposition at different places on the walls inside the chamber. The numerical prediction of the argon flow inside the spray chamber shows a typical swirling flow pattern, as expected in a cyclone chamber. The cyclone spray chamber works primarily like an impact chamber with regard to the deposition behaviour of the aerosol droplets, and not as a typical cyclone used in technical areas. The largest share of the nebulized sample (∼36%) is impacted directly onto the surface in front of the nebulizer. Approximately 17% is deposited on the rest of the curved surface in the plane of the nebulizer. About 29% is collected on the conical bottom, and ∼15% on the conical top of the spray-chamber, respectively. The simulation predicted a value of 2.0% for the aerosol yield at the outlet of the chamber; the experimentally determined value amounted to 2.4%. As can be seen from a comparison of the results obtained from experiment and CFD, computer simulation can be considered as a modern tool for helping to shed light on the processes occurring in spray chambers and for the prediction of their analytical performance.