Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 3 2 2003 10.5194/acp-3-325-2003 http://www.atmos-chem-phys.net/3/325/2003/ http://www.atmos-chem-phys.net/3/325/2003/acp-3-325-2003.html http://www.atmos-chem-phys.net/3/325/2003/acp-3-325-2003.pdf 325 334 2003-03-27 Emission of ions and charged soot particles by aircraft engines A. Sorokin X. Vancassel P. Mirabel Central Institute of Aviation Motors, 2 Aviamotornaya Str., 111116, Moscow, Russia Centre de Géochimie de la Surface, CNRS and Université Louis Pasteur 1, Rue Blessig, F-67084 Strasbourg France In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. For the engine considered, the upper limit for the ion emission index EI_i is of the order of (2-5) x10¹⁶ ions/kg-fuel if ion-soot interactions are ignored and the introduction of ion-soot interactions lead about to a 50% reduction. The results also show that most of the soot particles are either positively or negatively charged, the remaining neutral particles representing approximately 20% of the total particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002) shows an excellent agreement.