Numerical Study of the Influence of Droplet Injection Direction on Dust Particle Absorption

Introduction. One of the most effective technologies for removing dispersed impurities from gas is liquid purification, because inertial separators cannot capture fine particles. The challenge arises of increasing the efficiency of gas-dispersed media purification using this method. One way to solve this challenge is determining the injection angle of the droplet fractions at which the coagulation process will be most effective. Aim of the Study. The aim of the academic work was to study the effect of the injection direction of the droplet fraction jet on the intensity of the absorption of solid particles by liquid droplets. Materials and Methods. To describe the flow of a multiphase medium, there was used a continual approach for modeling the dynamics of inhomogeneous media, which involves solving a complete hydrodynamic system of motion equations for each mixture components. The dispersed phase was modeled as a multifractional polydisperse one; the dispersed phase fractions may differ in both the material density and the size of dispersed particles. There were taken into account interphase heat exchange and momentum exchange including the aerodynamic drag force, the dynamic Archimedes force, and the added mass force. The dynamics of the carrier medium was described by the Navier–Stokes system of equations for a viscous, compressible heat-conducting gas. The mathematical model also took into account the collisional coagulation of particles of different fractions. The system of the mathematical model equations was supplemented with boundary conditions. An explicit finite-difference method was used to integrate the equations of the mathematical model. A nonlinear correction scheme was used to overcome numerical oscillations. Results. There was simulated the injection of droplet fractions into a dust-laden flow at various angles to the channel wall. It has been found that the most intense decrease in the average density of the dust fraction is observed for an angle of φ = π/2. For gas-droplet flow injection angles of φ and π–φ, the distributions of the volumetric contents of the dust fraction are similar. The calculations have shown that for a wide range of droplet fraction sizes the highest velocity slip is observed for droplet injection perpendicular to the direction of dust-laden flow. Discussion and Conclusion. The identified patterns allow us to determine the injection direction of droplet fractions that maximizes the absorption of solid particles. The results can be used to optimize liquid purification technologies for gas-dispersed media. In the future, these results can be used to improve the efficiency of gas-liquid filters.