Multicomponent and multiphase fluid flow and the phenomena related to this type of flow are very important issues in many industrial and natural processes. One of the methods considered for simulating multiphase and multicomponent flows is the lattice Boltzmann method. However, the multiphase and multicomponent models used in the lattice Boltzmann method are not able to simulate flows with properties close to real physics in many cases. For example, the existing models, in simulating high-viscosity ratio and high-density ratio binary flow, face many problems. The stability and accuracy of a multi-component method for the simulation of flows with a wide range of viscosity ratios is an especially important capability for realistic applications. To study different two-phase phenomena and simulate two-phase processes, it is necessary to increase the capabilities of two phase and binary models. This study aims to provide a computationally stable and accurate method for sim-ulating high-viscosity-ratio multicomponent fluid flows by developing the lattice Boltzmann method. In this research, an attempt has been made to investigate the factors affecting on the stability of the pseudopotential multicomponent method to changing the viscosity of components. These modifications include changes in the collision operator and the method of exerting force term that is applied between the components (two immiscible fluids).Then, the ability of the modified model to simulate multicomponent high viscosity ratio fluid flow has been investigated, and the effect of different viscosity ratios on the binary fluid flow has been investigated. A GPU parallel CUDA code has been developed and is employed to study the proposed method. Then, the effect of viscosity ratio, surface contact angle, and surface tension on the fluid flow has been investigated. The use of different collision models and various boundary conditions have significant effects on the fluid flow simulation results in porous media. No systematic study of the porous media simulation using the proposed collision model in this study has been done. Therefore, an accurate eva‎luation of collision models and boundary conditions and the ability of these models to accurately simulate fluid flow from the Stokes regime to the inertia regime and higher Reynolds numbers in the porous medium has been investigated. Further, the proposed model’s ability to simulate the phenomena related to fluid flow in porous media, including the Capillary intrusion phenomenon and the capillary and viscosity fingering phenomenon has been investigated. Finally, the binary flow of water and oil in a real porous medium is simulated and the results are compared with experimental results. The results indicate that the proposed model has a high capability for simulating a high viscosity ratio in the two-component fluid flow and has high stability for fluid simulation with the viscosity near zero.

محمود اشرفي زاده

محمدرضا توكلي نژاد

احمدرضا پيشه ور، ابراهيم شيراني، جواد ابوالفضلي اصفهاني