Single-component Multiphase Lattice Boltzmann Research Articles

Pore-scale investigation on the effect of gas-liquid phase separation on reactive flow in a horizontal rough fracture using the lattice Boltzmann method

In this study, the effect of the gas-liquid phase separation caused by seawater boiling on the carbonate crack dissolution process was investigated using the lattice Boltzmann (LB) method at the pore scale. The gas-liquid two-phase flow with phase change, heat transfer, and solute transport is described by a single-component multiphase LB model, thermal LB model, and mass transport LB model, respectively. In addition, the dissolved solid mass is calculated via the Volume of Pixel method. The main conclusions are as follows: the phase separation negatively affects dissolution, especially in the upper boundary of the crack. Moreover, the negative effect is strengthened with the increase in inlet velocity and the decrease in crack width while the influence of wettability on dissolution is non-linear and its degree depends on the phase distribution of the two phases. In addition, slug flow greatly hinders solute transport but may accelerate the dissolution reaction near the inlet.

Lattice Boltzmann study of the interaction between a single solid particle and a thin liquid film

The isothermal single-component multi-phase lattice Boltzmann method (LBM) combined with the particle motion model is used to simulate the detailed process of liquid film rupture induced by a single spherical particle. The entire process of the liquid film rupture can be divided into two stages. In Stage 1, the particle contacts with the liquid film and moves into it due to the interfacial force and finally penetrates the liquid film. Then in Stage 2, the upper and lower liquid surfaces of the thin film are driven by the capillary force and approach to each other along the surface of the particle, resulting in a complete rupture. It is found that a hydrophobic particle with a contact angle of 106.7° shows the shortest rupture duration when the liquid film thickness is less than the particle radius. When the thickness of the liquid film is greater than the immersed depth of the particle at equilibrium, the time of liquid film rupture caused by a hydrophobic particle will be increased. On the other hand, a moderately hydrophilic particle can form a bridge in the middle of the liquid film to enhance the stability of the thin liquid film.

Simulation of multiple cavitation bubbles interaction with single-component multiphase Lattice Boltzmann method

Understanding the behavior of multiple cavitation bubbles and their interactions is important for developing deeper insight into cavitation phenomena. Using a revised single-component multiphase Lattice Boltzmann method, the weak and strong interactions between two neighboring cavitation bubbles and the mutual interaction among a cluster of cavitation bubbles are simulated. The simulated bubble evolutions have satisfying agreement with previous experimental results. Details of the multiple bubble interactions (the pressure and velocity fields) are presented. In the case of two-bubble interactions, typical phenomena such as bubble toroidal deformation, micro-jets, the thinning of the liquid film, and bubble coalescence are successfully reproduced. The bubble radius changes under two-bubble weak interaction are adequately described by a revised 2-D Rayleigh-Plesset equation. The transition from the strong to weak interactions with increasing initial distance between the two bubbles is analyzed. The behaviors of a cluster of bubbles are also simulated, where the shield effect of outer layer bubbles and the micro-jets are accurately captured. The present multiphase Lattice Boltzmann method is a promising tool to investigate complex cavitation problems.

Development and application of a high density ratio pseudopotential based two-phase LBM solver to study cavitating bubble dynamics in pressure driven channel flow at low Reynolds number

Abstract A pseudo-potential based single component multiphase Lattice Boltzmann flow solver was developed. Peng–Robinson equation of state was coupled with Exact Difference Method to incorporate interaction forces. This solver was developed for a D2Q9 lattice structure. The solver was thoroughly validated against several canonical problems like estimation of coexistence curve, surface tension estimation from Laplace Law and growth of a cavitating bubble in quiescent flow. The solver was found to be numerically stable for density ratios up to 103. The solver was then used to simulate bubble dynamics for cavitating flows in different flow configurations. Fluid flow characteristics of a single cavitating bubble for Poiseuille flow with stationary and non-stationary walls at Reynolds number of 1 and 10 were investigated. Temporal evolution of the bubble when it is placed along the channel centreline and at an offset is presented here.

Single-component multiphase lattice Boltzmann simulation of free bubble and crevice heterogeneous cavitation nucleation.

This work serves as an important extension of previous work on cavitation simulation [Sukop and Or, Phys. Rev. E 71, 046703 (2005)10.1103/PhysRevE.71.046703]. A modified Shan-Chen single-component multiphase lattice Boltzmann method is used to simulate two different heterogeneous cavitation nucleation mechanisms, the free gas bubble model and the crevice nucleation model. Improvements include the use of a real-gas equation of state, a redefined effective mass function, and the exact difference method forcing scheme. As a result, much larger density ratios, better thermodynamic consistency, and improved numerical accuracy are achieved. In addition, the crevice nucleation model is numerically investigated using the lattice Boltzmann method. The simulations show excellent qualitative and quantitative agreement with the heterogeneous nucleation theories.

Numerical prediction of thin liquid film near the solid wall for hydraulic cavitating flow in microchannel by a multiphase lattice Boltzmann model

Based on a multiphase lattice Boltzmann (LB) model integrating body forces such as inter-particle interaction force and fluid-solid interaction force, a numerical prediction of thin liquid film near the solid wall for hydraulic cavitating flow in microchannel is conducted in the present work. The validity of model is tested by means of Laplace law and experimental result. On this basis, a full thin liquid film near the solid wall is successfully predicted, which proves that the single-component multiphase LB model integrated with various interaction forces is a good solution to this type of problem like hydraulic cavitating flow in microchannel. The further simulation indicates that the fluid-solid interaction strength (gs) has a significant effect on the formation of thin liquid film. A critical value (gs = −3.5) of fluid-solid interaction strength is found, and thin liquid film fails to be predicted at gs > −3.5. A simple simulation on the contact angle (θ) of droplet on the solid surface is conducted to analyze the reason for this phenomenon. It is found that a full thin liquid film could be successfully predicted only when the solid surface is fully wetted by liquid, i.e., θ = 0° corresponding to gs ≤ −3.5. The current research provides a potential way for future investigation on heat transfer accompanied by hydraulic cavitating flow.

A thermal immiscible multiphase flow simulation by lattice Boltzmann method

The lattice Boltzmann (LB) method, as a mesoscopic approach based on the kinetic theory, has been significantly developed and applied in a variety of fields in the recent decades. Among all the LB community members, the pseudopotential LB plays an increasingly important role in multiphase flow and phase change problems simulation. The thermal immiscible multiphase flow simulation using pseudopotential LB method is studied in this work. The results show that it is difficult to achieve multi-bubble/droplet coexistence due to the unphysical mass transfer phenomenon of “the big eat the small” – the small bubbles/droplets disappear and the big ones getting bigger before a physical coalescence when using an internal energy based temperature equation for single-component multiphase (SCMP) pseudopotential models. In addition, this unphysical effect can be effectively impeded by coupling an entropy-based temperature field, and the influence on density fields with different energy equations are discussed. The findings are identified and reported in this paper for the first time. This work gives a significant inspiration for solving the unphysical mass transfer problem, which determines whether the SCMP LB model can be used for multi-bubble/droplet systems.

Numerical investigation of the pseudopotential lattice Boltzmann modeling of liquid–vapor for multi-phase flows

The incorporation of different equations of state into single-component multiphase lattice Boltzmann model is considered in this paper. The original pseudopotential model is first detailed, and several cubic equations of state, the Redlich–Kwong, Redlich–Kwong–Soave, and Peng–Robinson are then incorporated into the lattice Boltzmann model. A comparison of the numerical simulation achievements on the basis of density ratios and spurious currents is used for presentation of the details of phase separation in these non-ideal single-component systems. The paper demonstrates that the scheme for the inter-particle interaction force term as well as the force term incorporation method matters to achieve more accurate and stable results. The velocity shifting method is demonstrated as the force term incorporation method, among many, with accuracy and stability results. Kupershtokh scheme also makes it possible to achieve large density ratio (up to 104) and to reproduce the coexistence curve with high accuracy. Significant reduction of the spurious currents at vapor–liquid interface is another observation. High-density ratio and spurious current reduction resulted from the Redlich–Kwong–Soave and Peng–Robinson EOSs, in higher accordance with the Maxwell construction results.

Lattice Boltzmann Simulations for Thermal Vapor-Liquid Two-Phase Flows

Lattice Boltzmann model with a double distribution functions are used to simulate thermal vapor-liquid two-phase flow. In this model, the single component multi-phase lattice Boltzmann model proposed by Zhang and Chen is used to simulate the fluid dynamics. The internal energy is simulated by using a energy distribution functions. By coupling the fluid dynamics and internal energy field through a suitably defined density term, the thermal gas-liquid phase flows are simulating. Numerical results on phase separation show the coexistence curves of numerical simulations are in good agreement with the theoretical predictions for the density of gas-liquid phase, and the internal energy of gas is higher than the internal energy of liquid at the same reduced temperature.

A Thermal Lattice Boltzmann Two-Phase Flow Model and Its Application to Heat Transfer Problems—Part 1. Theoretical Foundation

A new and generalized lattice Boltzmann model for simulating thermal two-phase flow is described. In this model, the single component multi-phase lattice Boltzmann model proposed by Shan and Chen is used to simulate the fluid dynamics. The temperature field is simulated using the passive-scalar approach, i.e., through modeling the density field of an extra component, which evolves according to the advection-diffusion equation. By coupling the fluid dynamics and temperature field through a suitably defined body force term, the thermal two-phase lattice Boltzmann model is obtained. In this paper, the theoretical foundations of the model and the validity of the thermal lattice Boltzmann equation method are laid out, illustrated by analytical and numerical examples. In a companion paper (P. Yuan and L. Schaefer, 2006, ASME J. Fluids Eng., 128, pp. 151–156), the numerical results of the new model are reported.