The relevance of the discussed issue is caused by the wide spread of turbulent particle-laden flows in different technical equipment and facilities used in extraction of mineral resources, transportation technologies, energy engineering and other branches of industry. The examples are the pneumatic transport systems for powders, tunnels of underground excavations, gas pipes of boiler houses and metallurgy plants, ventilation channels of plants, steam pipelines and other elements of steam power plants etc. The important role of particleladen flows in nature and human activities dictates the necessity of the study of key mechanisms of the particle-wall interaction and the development of the advanced engineering turbulence models for two-phase flows. The main aim of the study is to obtain the analytical expression for particle concentration in turbulent channel flow between two plates from the asymptotic analysis of the kinetic equation for probability density function of particle velocity and position and the classical scaling theory of wall turbulence; analysis of finite particle size effect on accumulation of particles in viscous sublayer of wall turbulence. The methods: the asymptotic analysis of kinetic equation for probability density function of particle velocity and position; Chapman-Enskog method for finding a solution of the kinetic equation; scaling and dimensional arguments. The results: The authors have carried out the asymptotic analysis of the kinetic equation for probability density function of particle velocity and position for turbulent particle-laden flow in a plane channel. General forms of the expressions for concentrations of particles are obtained for viscous sublayer, logarithmic and outer layer. The authors proposed a new particle accumulation criterion. The analytical expression was obtained for this criterion. The expression shows the drastic increase of particle concentration in the viscous sublayer when increasing the Stokes number from 1 to 27, which is in good agreement with the data of DNS/Lagrangian tracking simulations. It is shown that the increase of particle size attenuates the particle accumulation. The analytical expression for concentration of particles in the viscous sublayer is derived. It is in good agreement with the data of DNS/Lagrangian tracking simulations.
|Журнал||Известия Томского политехнического университета. Инжиниринг георесурсов|
|Состояние||Опубликовано - 2018|