Heterogeneous nucleation in multi-component vapor on a partially wettable charged conducting particle. I. Formulation of general equations: electrical surface and line excess quantities

Thermodynamics is applied to formulate general equations for internal energies and grand potential for a system consisting of a dielectric liquid nucleus of a new phase on a charged insoluble conducting sphere within a uniform macroscopic one- or multicomponent mother phase. The currently available model for ion-induced nucleation assumes complete spherical symmetry of the system, implying that the seed ion is immediately surrounded by the condensing liquid from all sides. We take a step further and treat more realistic geometries, where a cap-shaped liquid cluster forms on the surface of the seed particle. To take into account spontaneous polarization of surface layer molecules we introduce the electrical surface and line excess quantities.

Modelling binary homogeneous nucleation of water-sulfuric acid vapours: parameterisation for high temperature emissions

Particles formed in the automobile exhaust might form a significant fraction of fine particles in urban air. We have developed a model and produced parametrizations for predicting the particle formation rate at exhaust conditions. We studied the formation in the mixture of water and sulfuric acid vapors and at temperatures between 300 and 400 K. A thermodynamically consistent version of the classical binary homogeneous nucleation model was used. The needed thermodynamical input data (vapor pressures, chemical activities, surface tensions, densities) are carefully investigated and utilized in thermodynamically consistent way. The obtained nucleation rates are parametrized in order to be able to use this nucleation model in aerosol dynamic models, exhaust models, or other process models. The parametrization reduces computational time at least by a factor of 500.