Hydrodynamic aspects of modeling of the mass transfer and coagulation processes in turbulent accretion disks

This paper considers, in the context of modeling the evolution of a protopl anetary cloud, the hydrodynamic aspects of the theory of concurrent process es of mass transfer and coagulation in a two-phase medium in the presence o f shear turbulence in a differentially rotating gas-dust disk and of polydi sperse solid particles suspended in a carrying flow of solid particles. The defining relations are derived for diffuse fluxes of particles of differen t sizes in the equations of turbulent diffusion in the gravitational field, which describe the convective transfer, turbulent mixing, and sedimentatio n of disperse dust grains onto the central plane of the disk. as well as th eir coagulation growth. A semiempirical method is developed for calculating the coefficients of turbulent viscosity and turbulent diffusion for partic les of different kinds. This method takes into account the inverse effects of dust transfer on the turbulence evolution in the disk and the inertial d ifferences between disperse solid particles. To solve rigorously the proble m of the mutual influence of the turbulent mixing and coagulation kinetics in forming the gas-dust subdisk, the possible mechanisms of gravitational, turbulent, and electric coagulation in a protoplanetary disk are explored a nd the parametric method of moments for solving the Smoluchowski integro-di fferential coagulation equation for the particles' size distribution functi on is considered. This method takes into account the fact that this distrib ution belongs to a definite parametric class of distributions.