Das Projekt "Aerosoldynamik" wird vom Umweltbundesamt gefördert und von Universität Duisburg, Fachbereich 9 Elektrotechnik, Fachgebiet Prozess- und Aerosolmesstechnik durchgeführt. An aerosol is a suspension of solid and/or liquid particles in a gas. Aerosol dynamical processes are used in the production of materials for high-technology applications such as optical waveguides, thin films for microelectronics, quantum dots and powders for the manufacture of advanced ceramics, as well as technical products such as pigments and carbon blacks. However, aerosols can also affect human health and the environment. Basic similarities exist in technical as well as natural aerosoldynamical processes. Since an aerosol is a dynamical system, interactions between particles, between particles and surrounding surfaces as well as exchanges between the gas-phase and the particles will occur. These aerosoldynamical processes are studied in this project. Chemical reactions are not treated yet. Particle transport due to convection, diffusion and temperature gradients as well as condensation and evaporation of vapor material onto the particles are dealt with. In order to optimize aerosol processes and to minimize the impact of hazardous aerosols to the environment we model the aerosoldynamical processes in fluid flows. The developed model is capable of describing two-dimensional problems. The effect of particle coagulaiton,and especially electrical coagulation, i.e. the coagulation of charged particles, is of current interest. The coagulation process of like charged particles, i.e. particles of the same polarity, is slower than between uncharged particles. While uncharged particles from due to coagulation a so-called 'self preserving size distribution' like charged particles tend to form a monodisperse aerosol. However, the coagulation process of unlike charged particles is also investigated, which is of interest for gas-cleaning purposes. The coagulation process is enhanced due to the attractive force between unlike charged particles, but due to recombination of charges during the coagulation process, it slows down and Brownian coagulation remains. There are two ways in which coagulation between oppositely charged particles can occur. The first method is the miexing of two oppositely charged aerosols, having different mean geometric sizes. Since the coagualtion between unequal sized particles is always higher than between equal sized particles the two aerosols will collide very rapidly with each other. Due to the fact that larger particles can be charged more efficiently than smaller particles, this technique provides a good scavening method to the smaller particles. The second method is the bipolar charging of the aerosol, such that half of the particles are charged positively and half of them negatively. Here the coagulaiton process reduces the charges on the particles after collision in a way, that the electrical enthancement decreases very rapidly.