Abstract

This dissertation enhances the understanding of multiphase flows at the pore scale through the application and advancement of lattice–Boltzmann (LB) models. It explores key aspects of multiphase flows, significantly contributing to both theoretical and practical domains of fluid dynamics. A detailed assessment of the pseudopotential LB method is conducted, focusing on its thermodynamic consistency, the relationship between density and surface tension, and its applicability to real fluids. This evaluation reveals the strengths and limitations of existing pseudopotential models, providing insights into their ability to capture the essential physics of multiphase systems.

The research applies the pseudopotential LB model to simulate the binary collision of picoliter water droplets, a process relevant to various engineering and scientific applications. This application demonstrates the model’s capability to capture the complex interactions of forces during droplet collisions, offering new perspectives on the multiscale dynamics of multiphase flows. Additionally, the dissertation extends the LB method to study CO2 desublimation on cryogenic surfaces at the pore scale, providing a comprehensive understanding of the transient behavior of CO2 phase changes and the evolution of porous structures.

To support these investigations, an in-house and object-oriented simulation framework, coupled with Message-Passing Interface (MPI) capabilities for parallel high-performance computing (HPC), named KAUST Lattice Boltzmann (KLB), was developed in C++. This work not only revisits recent advancements in the theoretical framework of the LB method for multiphase flow modeling but also offers practical tools and insights for tackling complex fluid dynamics challenges in engineering and environmental science.