Volatile particles formation during PartEmis: a modelling study

Abstract. A modelling study of the formation of volatile particles in a combustor exhaust has been carried out in the frame of the PartEmis European project. A kinetic model has been used in order to investigate nucleation efficiency of the H₂O-H₂SO₄ binary mixture in the sampling system. A value for the fraction of the fuel sulphur S(IV) converted into S(VI) has been indirectly deduced from comparisons between model results and measurements. In the present study, ranges between roughly 2.5% and 6%, depending on the combustor settings and on the value assumed for the parameter describing sulphuric acid wall losses. Soot particles hygroscopicity has also been investigated as their activation is a key parameter for contrail formation. Growth factors of monodisperse particles exposed to high relative humidity (95%) have been calculated and compared with experimental results. The modelling study confirms that the growth factor increases as the soot particle size decreases.