Lattice Boltzmann Method For The Simulation Of Two-phase Flow Based On The Rk Model

Two-phase flow is a kind of widespread physical problem.If its flow pattern and flow behavior can be predicted accurately by the numerical simulation,it will be of great value to the work and life.Different from the single phase flow,there exists the mobile phase interface in the process of immiscible two-phase flows.The flows is influenced by many factors and quite complicated.So the traditional numerical simulation method in this field has many limitations.The lattice Boltzmann method witch is a kind of mesoscopic method based on the theory of molecular motion is a new effective method for physical problems.In this paper,the research content derived from the national natural science fund project named "the numerical simulation research of viscoelastic fluid extrusion swelling and multiphase flow based on the lattice Boltzmann method "and aims to build a lattice Boltzmann model to simulate the two-phase fluid flow.In this paper,based on the two-phase color model,the influence of different parameter on the square cavity inlet flow is studied by using Lattice Boltzmann method.The numerical results show that the interfacial tension factor can influence the flow behavior obviously.too high or too low of this parameter will not conducive to forming a relatively stable phase interface;At the same time density ratio y and inlet velocity u0 will influence the width of the fluid in vertical direction to some extent when a stable phase interface have formed;Fluid flow in square cavity will produce disturbance to the other phase fluid,so that there will be a vortex appearing in the upper and lower boundary area,interfacial tension factor Ak and the inlet velocity u0 will affect the shape and the location of the vortex to some extent.Then the square cavity inlet flow of the powerlaw-Newton two-phase fluid are simulated by using the same calculation model with the addition of Powerlaw model.And on this basis explore the influence of power-law index and the inlet velocity on the flow behavior.The results show that the power law index significantly affected the flow patterns,velocity distribution and viscosity distribution of powerlaw fluid in a square cavity.Besides with the increase of inlet velocity,there will make horizontal velocity and viscosity distribution more uneven in the flow field,and be more vortex.Finally a co-extrusion flow of Newton-Newton two-phase fluid and powerlaw-Newton two-phase fluid in the parallel plate are simulated by using RK model respectively.The influence of viscosity and density on Newtonian fluid and the influence of the power-law index and the inlet velocity on power-law fluid are discussed respectively.