Using the Onsager variational principle, we study the dynamic coupling between the stress and the composition in a polymer solution. In the original derivation of the two-fluid model of Doi and Onuki the polymer stress was introduced a priori; theref...
Segregated flow, including stratified and annular flows, is commonly encountered in several practical applications such as chemical, nuclear, refrigeration, and oil and gas industries. Accurate prediction of liquid holdup and the pressure gradient is...
The two-fluid model (TFM) has become a foundational tool in numerical codes used for engineering analyses of two-phase flows in energy systems. However, its completeness remains a topic of debate because improper modeling of interfacial inertial coup...
This work presents an integrated multiphase flow model for downhole pressure predictions with the purpose of producing relatively more accurate predictions under wide-flowing conditions while maintaining a simple form. As a component of the integrate...
The efficient use of renewable energy is receiving more and more attention in the context of “carbon neutrality” and “carbon peaking”. For a long time, biomass has been used less efficiently as a renewable energy source, but w...
This article proposes a numerical resolution of a one-dimensional (1D), transient, simplified two-fluid model regularized with an artificial diffusion term for modeling stratified, wavy and slug flow in horizontal and nearly horizontal pipes. Artific...
Flow boiling within conventional, mini and micro-scale channels is encountered in a wide range of engineering applications such as nuclear reactors, steam engines and cooling of electronic devices. Due to the high complexity and importance of the boi...
The complexity of flashing flows is increased vastly by the interphase heat transfer as well as its coupling with mass and momentum transfers. A reliable heat transfer coefficient is the key in the modelling of such kinds of flows with the two-fluid...
Two-fluid formalisms that fully account for all complex inter-phase interactions have been developed based on a rigorous ensemble-averaging procedure. Here, we apply equilibrium approximation to particle velocity to simplify two-phase flow equations...
In this study, we present, test, and make available to the scientific community the betaSigmaSlurryFoam solver, which is a two-phase model based on the Eulerian-Eulerian approach for the simulation of turbulent slurry transport in piping systems. Spe...
Proper selection and application of interfacial friction factor correlations has a significant impact on prediction of key flow characteristics in gas–liquid two-phase flows. In this study, experimental investigation of gas–liquid flow in a vertical...
This study aims to investigate the pressure changes, bubble dynamics, and flow physics inside the U- and C-shaped pipes with four different gravitational directions. The simulation is performed using a 1D centerline-based mesh generation technique al...
Compound parabolic concentrator (CPC) photocatalytic reactors are commonly used for photocatalytic water splitting in hydrogen production. This study aimed to gain a better understanding of the physical processes in CPC photocatalytic reactors and pr...
In this paper, liquid coatings of bubbly flow with peristaltic motion inside elastic walls is investigated. The proposed model is constructed using the two-fluid approach with the most distinctive collaboration among gas, fluid, pressure, and drag fo...
To this day, the nature of dark matter (DM) remains elusive despite all our efforts. This type of matter has not been directly observed, so we infer its gravitational effect. Since galaxies and supermassive objects like these are most likely to conta...
We study shear banding in a planar 4:1 contraction flow using our recently developed two-fluid model for semidilute entangled polymer solutions derived from the generalized bracket approach of nonequilibrium thermodynamics. In our model, the differen...
Oil mist lubrication can be utilized as an emergency lubrication system in the main reducer of a helicopter. A special-design pneumatic two-fluid nozzle is the crucial system component for atomizing lubricant oil, so exploring the atomization charact...
Due to the unclear seepage mechanism for shale oil, it is hard to establish a reasonable mathematical model to describe the flowing law. In this study, a real shale pore structure was reconstructed with CT scanning and a numerical model of fluid flow...
Boiling conjugate heat transfer is an active field of research encountered in several industries, including metallurgy, power generation and electronics. This paper presents a computational fluid dynamics approach capable of accurately modelling the...
The hydrodynamic performance of the wave power extraction of an innovative modified breakwater-integrated Oscillating Water Column (OWC) wave energy converter is both numerically and experimentally presented in this study. The modified OWC device com...
In this study, a two-dimensional computational domain featuring gas and solid phases is computationally studied for Geldart-B-type particles. In addition to the baseline case of a uniform gas-phase injection velocity, three different inlet velocity p...
Resolving the interaction between soil and water is critical to understanding a wide range of geotechnical applications. In cases when hydrodynamic forces are dominant and soil fluidization is expected, it is necessary to account for the microscale i...
Limiting global temperature rise to well below 2 °C according to the Paris climate accord will require accelerated development, scale-up, and commercialization of innovative and environmentally friendly reactor concepts. Simulation-based design c...
The two-fluid model (TFM) coupled with the kinetic theory of granular flow (KTGF) has gradually been used for modeling dense granular flows and mixing in rotating drums in recent years. In the present paper, a review is made from the perspective of m...
Hydrogen-based direct reduction (H-DR) represents an environmentally benign and energy-efficient alternative in ironmaking that has significant industrial potential. This study reviews the current status of H-DR shaft furnaces and accompanying hydrog...
The flow of viscoelastic fluids may, under certain conditions, exhibit shear-banding characteristics that result from their susceptibility to unusual flow instabilities. In this work, we explore both the existing shear banding mechanisms in the liter...
Rod bundle flow is an important research field related to reactor cooling in nuclear power plants. Owing to the rapid development of computerized performance assessments, interest in coolant flow analysis using computational fluid dynamics has garner...
The pyrolysis of biomass in a fluidized-bed reactor is studied by a combination of a CFD-DEM algorithm and a multistep kinetic scheme, where fluid dynamics, heat and mass transfer, particle collisions, and the detailed thermochemical conversion of bi...
The present research describes the design, analysis, and modeling of an air-granular particle fluidized-bed system with dimensions of 0.08 m × 0.4 m × 0.08 m. The hydrodynamic and thermal experiments are designed to verify the numerical m...
Flashing flows of initially sub-cooled water in a converging–diverging nozzle is investigated numerically in the framework of the two-fluid model (TFM). The thermal non-equilibrium effect of phase change is considered by an interfacial heat tra...
CFD simulations of the multiphase flow in technical equipment are feasible within the framework of interpenetrating continua, the so-called two-fluid modelling. Predictions with multiphase CFD are only possible if a fixed set of closures for the inte...
Multiphase flow in annular channels is complex, particularly in the region where the flow direction abruptly changes between the inner pipe and the outer pipe, as the cases in horizontal drilling and pneumatic conveying. Simplified models and experie...
The hole cleaning device is a powerful application which can effectively slow down the deposition of cuttings during drilling. However, in this complicated swirl flow created by the device, the decay of the swirl flow and the particle behavior are no...
In the present study, a mathematical model of the isobutane dehydrogenation process for a laboratory reactor with a diameter of 2.8 cm and a height of 70 cm was created using CFD methods. A two-fluid model was selected as a model for the fluidization...
The in vitro fabrication of big osteoarticular implants integrating biomaterials and cells is of tremendous interest because these tissues have a limited ability to regenerate. However, the growth of such cells in vitro is highly problematic, especia...
Bubble flow can be simulated by the two-fluid model and the multi-fluid model based on the Eulerian method. In this paper, the gas phase was further divided into several groups of dispersed phases according to the diameter by using the Eulerian-Euler...
Biomass as a clean and renewable source of energy has immense potential to aid in solving the energy crisis in the world. In order to accurately predict the fluidization behavior of biomass particles using the Eulerian–Eulerian approach and the...
This contribution underscores the importance of selecting an appropriate interphase momentum transfer model for accurately predicting the distribution of the solid phase in a full-scale circulating fluidized bed (CFB) riser equipped with a smooth C-t...
In this paper, a new type of water pressure and air pressure composite slurry is proposed to ensure the safety of spraying. Firstly, the air tightness, bending resistance and viscosity of the spraying material were measured in the laboratory. Secondl...
In view of the problems of traditional spraying technology, such as complex processes, high costs, large dust amounts, and poor air leakage effects, a new composite spraying slurry is proposed in this paper, which takes clay as the main base material...
Large-eddy simulations have been conducted for two-phase flow (water and air) in a hydrocyclone using Two-Fluid (Euler–Euler) and Volume-of-Fluid (VOF) models. Subgrid stresses are modeled using a dynamic eddy–viscosity model, and results are compare...
The precise design of heat exchangers in automobile air conditioning systems for more sustainable electric vehicles requires an enhanced assessment of CFD mechanistic models for the subcooled boiling flow of pure eco-friendly refrigerant. Computation...
11 September 2019
In this paper, a mathematical model based on the two-fluid (Euler–Euler) frame model for wet dedusting process is proposed. The model considers in detail the aggregation of particles and droplets caused by turbulence and Brownian diffusion as w...
Hydrogen storage is a promising technology for storage of renewable energy resources. Despite its high energy density potential, the development of hydrogen storage has been impeded, mainly due to its significant cost. Although its cost is governed m...
Traditional models of two-fluid flow through porous media at the macroscale have existed for nearly a century. These phenomenological models are not firmly connected to the microscale; thermodynamic constraints are not enforced; empirical closure rel...
A numerical model was developed to simulate a fluidized bed reactor for isobutane dehydrogenation. First, we constructed a hydrodynamic model of catalyst particle fluidization and a kinetic model for three chemical reactions in a simple lab-scale rea...
Bubble columns are used in many different industrial applications, and their design and characterisation have always been very complex. In recent years, the use of Computational Fluid Dynamics (CFD) has become very popular in the field of multiphase...
The flashing phenomenon is relevant to nuclear safety analysis, for example by a loss of coolant accident and safety release scenarios. It has been studied intensively by means of experiments and simulations with system codes, but computational fluid...
30 August 2023
A hybrid two-phase flow solver is proposed, based on an Euler–Euler two-fluid model with continuous blending of a Volume-of-Fluid method when phase interfaces of coherent gas pockets are to be resolved. In a preceding study on a two-dimensional...
Slurry pipe transport has directed the efforts of researchers for decades, not only for the practical impact of this problem, but also for the challenges in understanding and modelling the complex phenomena involved. The increase in computer power an...
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