Article
Computer Science, Interdisciplinary Applications
Chunhua Zhang, Lian-Ping Wang, Hong Liang, Zhaoli Guo
Summary: In this paper, a central moment discrete unified gas-kinetic scheme (DUGKS) is proposed for multiphase flows with large density ratio and high Reynolds number. Two sets of kinetic equations are used to approximate the incompressible Navier-Stokes equations and a conservative phase field equation for interface-capturing. The DUGKS framework defines velocity as the first moment of the distribution function for the hydrodynamic equations and carefully defines the zeroth moments to recover an artificial pressure evolution equation. Benchmark tests are conducted to demonstrate the capabilities of the proposed scheme, and the numerical results are in good agreement with theoretical and experimental data.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Mechanics
Ellen K. Luckins, James M. Oliver, Colin P. Please, Benjamin M. Sloman, Robert A. Van Gorder
Summary: The study focuses on endothermic reactions and the flow of granular solid reactants powered by hot gas counter-current flow. It explores various heat-transfer rate values and identifies six distinguished limits, with a diffusive boundary layer for high temperatures. The research shows that the direction of net heat flux affects the solution structure in the single-temperature limit.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Qiang He, Weifeng Huang, Yuan Yin, Yang Hu, Decai Li
Summary: In this paper, a lattice Boltzmann model with dynamic grid refinement is proposed for simulating immiscible ternary flows. The model is able to conserve the total mass and preserve the volume of each phase, while avoiding the presence of unphysical fluids by introducing a source term into the interface capturing equation. The accuracy and applicability of the model are evaluated through simulations of several typical problems.
Article
Mathematics, Applied
Qiaozhong Li, Xiaodong Niu, Zhiliang Lu, You Li, Adnan Khan, Zishu Yu
Summary: An improved single-relaxation-time multiphase lattice Boltzmann method is developed for simulating multiphase flows with large density ratios and high Reynolds numbers, showing good stability and reliability in complex multiphase flow simulations.
ADVANCES IN APPLIED MATHEMATICS AND MECHANICS
(2021)
Article
Mechanics
Zhangrong Qin, Jianfei Zhu, Wenbo Chen, Chengsheng Li, Binghai Wen
Summary: In this paper, an effective pseudo-potential lattice Boltzmann model is developed to achieve thermodynamic consistency, extremely large density ratio, and adjustable surface tension. By decoupling the mesh space from the momentum space and using a high-precision explicit finite difference method, the accuracy and stability of the simulation are improved.
Article
Physics, Applied
Yukun Liu, Jasmine C. Sabio, Ryan L. Hartman
Summary: An atmospheric, dielectric-barrier discharge mu-plasmatron was utilized to synthesize a methylated organometallic complex. The micropillars in a staggered configuration served as a porous media for 2D mixing, with longitudinal dispersion characterized by an axial dispersion model. The technique allowed for stable plasma excitation of methane-helium gas mixtures and in-situ formation of methyl radicals.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Energy & Fuels
Jinya Zhang, Hangyu Chen, Ye Zhou, Guangda Cao
Summary: This study investigated the collision mechanisms and influencing factors in the air floatation deoiling process, proposed improvement measures, and established a simulation method. The simulation results showed that the oil-gas diameter ratio, collision angle, and interphase force between oil and gas affect the collision results.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Nanoscience & Nanotechnology
G. G. Pereira
Summary: This study focuses on the flow of two immiscible fluid components with large density and viscosity ratios. By using a pseudo-potential lattice Boltzmann model, the researchers have developed a model that successfully passes benchmark tests and shows no discontinuities in velocity profiles at interfaces. The model has been applied to the study of rising bubbles and flow in porous media, and it demonstrates good quantitative agreement with previous numerical and experimental results, as well as physical consistency with established experimental observations.
Article
Mechanics
Xin Lai, Shaofan Li, Jiale Yan, Lisheng Liu, A-Man Zhang
Summary: This study investigates the dispersion of virus-laden droplets in coughing jets using large-eddy simulations. The turbulence of the jet determines the droplets' dispersion, and the droplet particles increase the complexity of the turbulence. The spreading distance of droplets often exceeds the recommended social distancing rules, highlighting the importance of protective measures.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mathematics, Applied
Xiaolei Yuan, Yao Wu, Chunhua Zhang, Zhenhua Chai, Baochang Shi
Summary: In this work, we propose a unified framework of phase-field-based multiple-relaxation-time lattice Boltzmann (MRT-LB) method for incompressible multiphase flows with density and viscosity contrasts. The framework includes the classic MRT-LB model and central-moments-based LB model (CLBM). The governing equations of incompressible multiphase flows can be accurately reproduced through direct Taylor expansion method at the second-order of expansion parameters. The present model shows better numerical stability and accuracy compared to the traditional Bhatnagar-Gross-Krook (BGK) model, and is capable of simulating multiphase flow problems with large density ratio (1000).
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2023)
Article
Mechanics
A. K. Aiyer, C. Meneveau
Summary: In this study, the dispersion characteristics of slightly buoyant droplets in a turbulent jet were investigated using large eddy simulations (LES). The model accurately captured the differential, size-based dispersion characteristics of the droplets with finer grid resolutions. Moreover, similarity solution and subgrid-scale models were used to predict the concentration profiles and turbulent concentration flux of the droplets, and the results showed good agreement with experimental data and high-resolution LES simulations.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Cosan Daskiran, Fangda Cui, Michel C. Boufadel, Ruixue Liu, Lin Zhao, Tamay Ozgokmen, Scott Socolofsky, Kenneth Lee
Summary: Understanding the size of oil droplets released from a jet in crossflow is crucial for estimating the trajectory of hydrocarbons and the rates of oil biodegradation/dissolution in the water column. Experimental results and simulations show that the size of oil droplets increases with elevation across the plume, likely due to the individual rise velocity of droplets. The simulation effectively captures the top and bottom boundaries of the plume, with smaller droplets observed at the center axis compared to the side boundaries due to the formation of counter-rotating vortex pair.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Electrochemistry
A. N. Colli, J. M. Bisang
Summary: In this study, a solver was developed and implemented in the OpenFOAM framework to predict the current distribution in gas evolving electrochemical reactors. The solver considers both liquid and gas flows under turbulent conditions and takes into account a range of bubble sizes. The results show that the solver is capable of accurately predicting the behavior of such electrochemical systems.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Mechanics
Zhenlin Guo, Fei Yu, Ping Lin, Steven Wise, John Lowengrub
Summary: A new two-phase fluid model, q-NSCH-DD, is proposed to simulate two-phase flows with moving contact lines in complex geometries while maintaining thermodynamic consistency. Numerical analysis confirms the effectiveness and accuracy of the model.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mathematics, Applied
M. Najafian, M. S. Mortazavi
Summary: This paper investigates the evaporation of droplets and proposes a two-step algorithm to solve problems with high-density ratios. The results demonstrate the accuracy and feasibility of this modified method.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2023)