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Abstract

The principal subject of this study is the modelling of the condensation of steam into and evaporation of water from aerosol particles. These processes introduce a new type of term into the equation of the aerosol particle size distribution. This new term faces the code developer with three major problems: the physical modelling of the condensation - evaporation process, the discretion of the new term and the separate accounting for the masses of the water and of the other components. This study has considered four codes which model the condensation of steam into and its evaporation from aerosol particles: AEROSYM-M (UK), AEROSOLS/B1 (France), NAUA (Federal Republic of Germany) and CONTAIN (USA). The modelling in the codes has been addresses under three headings. These are the physical modelling of condensation, the mathematics of the discretization of the equations, and the methods for modelling the separate behaviour of different chemical components of the aerosol. The codes are least advanced in area of solute effect modelling. At present only AEROSOLS/B1 includes the effect. The effect is greater for more concentrated solutions. Codes without the effect will be more in error (underestimating and total airborne mass) the less condensation they predict. Data are needed on the water vapour pressure above concentrated solutions of the substances of interest (especially CsOH and CsI) if the extent to which aerosols retain water under superheated conditions is to be modelled.

Additional information

Authors: DUNBAR I H UKAEA SAFETY AND RELIABILITY DIRECTORATE, CULCHETH, WARRINGTON (UK), UKAEA SAFETY AND RELIABILITY DIRECTORATE, CULCHETH, WARRINGTON (UK)
Bibliographic Reference: EUR 10584 EN (1986) MF, 68 P., BFR 150, BLOW-UP COPY BFR 350, EUROFFICE, LUXEMBOURG, POB 1003
Availability: Can be ordered online
Record Number: 1989124136200 / Last updated on: 1987-01-01
Category: PUBLICATION
Available languages: en