Miscibility Regimes in a 23Na–39K Quantum Mixture

The effects of miscibility in interacting two-component classical fluids are relevant in a broad range of daily applications. When considering quantum systems, two-component Bose–Einstein condensates provide a well-controlled platform where the miscible–immiscible phase transition can be completely characterized. In homogeneous systems, this phase transition is governed only by the competition between intra- and inter-species interactions. However, in more conventional experiments dealing with trapped gases, the pressure of the confinement increases the role of the kinetic energy and makes the system more miscible. In the most general case, the miscibility phase diagram of unbalanced mixtures of different atomic species is strongly modified by the atom number ratio and the different gravitational sags. Here, we numerically investigate the ground-state of a 23Na–39K quantum mixture for different interaction strengths and atom number ratios considering realistic experimental parameters. Defining the spatial overlap between the resulting atomic clouds, we construct the phase diagram of the miscibility transition which could be directly measured in real experiments.

A lattice Boltzmann study of dynamic immiscible displacement mechanisms in pore doublets

An advanced chromodynamics, Rothmann-Keller (RK) type lattice Boltzmann model (LBM) is used in this study. The new model benefits from high stability and capability of independently setting the interfacial tension of the fluids as an input parameter. In addition, the model is coupled with a wall-density approach to simulate the hydrophilic or hydrophobic properties of wall surfaces. Finally, injection of a wetting (non-wetting) fluid in a pore doublet geometry which is initially filled with non-wetting (wetting) fluid is simulated. The results of simulation reveal the capability of RK-LBM to simulate relative permeabilities of fluids in porous media for future studies of two-immiscible phase flow in various geoenvironmental problems.

Pore-Scale Study of the Thermochemical Process in Porous Media With Immiscible Phase by Lattice Boltzmann Method

Reactive flow happens in carbonate rocks which are porous media during acidification. In this study, a thermochemical dissolution model based on the lattice Boltzmann method (LBM) is established to investigate the complex thermochemical process in porous media with immiscible phase at pore scale. In the model, the immiscible fluid flow, solute transport, and heat transfer are solved by Shan–Chen multicomponent LB model, mass transport LB model, and multicomponent thermal LB model, respectively. The porous media is generated by the quartet structure generation set, and the evolution of solid phase is addressed by volume of pixel (VOP) method. The detailed thermochemical process in porous media with immiscible phase is revealed, and the effects of velocity, concentration, and temperature on mass and heat transfer are further analyzed. The results show that increasing inlet velocity, inlet concentration, and temperature accelerates acidizing process and influences the temperature evolution in porous media significantly.