Abstract:
The paper presents a numerical solution to the problem of coagulation of solid particles and droplets during the injection of a gas-droplet flow into a gas suspension flow. It was assumed that a dusty medium moves in a flat channel, and a gas-droplet mixture is blown through the side surface of the channel. As a result of the coagulation of solid particles and droplets, the average density of the solid particle fraction decreases and the fractional composition of the droplet mixture changes. The calculations are based on a mathematical model of the dynamics of a polydisperse multi-velocity and multi-temperature gas suspension with a Lagrangian model of particle coagulation with relative velocity sliding. The mathematical model implemented a continuum technique for modeling the dynamics of multiphase media, which makes it possible to take into account the interphase interaction. The dynamics of the carrier medium is described by the Navier – Stokes equations for a compressible heat-conducting gas with interphase heat and momentum exchange. The aerodynamic drag force, the added mass force, and the dynamic Archimedes force were taken into account. The dispersed phase consisted of a number of fractions differing in the size of dispersed inclusions and the density of the particle material. The hydro- and thermodynamics of each dispersed fraction were described by a system of hydrodynamic equations, including the continuity equation, the equations for the conservation of momentum components, and the equation for the conservation of thermal energy, written taking into account the interphase thermal and force interaction. The system of equations for the dynamics of a multi-velocity multi-temperature polydisperse system was integrated by the explicit finite-difference McCormack method. The monotonicity of the solution was ensured by a nonlinear correction scheme. As a result of the calculations, time and space dependencies were obtained that characterize the evolution of the composition of a multi-fraction system when mixing flows of different dispersion.
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