## What is/are Multiphase Flow?

Multiphase Flow - Second, we characterized the multiphase flow with a high-speed camera and underwater hydrophone measurements, focusing on the cavitation effects, inside the cooling channels.^{[1]}Dimensionless numbers controlling the multiphase flow were deduced to understand the scaling law of the flow process.

^{[2]}2D Rectangular columns, formed within a thin gap between two enclosed parallel plates, are often used in visualisation and CFD studies of multiphase flows.

^{[3]}The structure of an ETV is very simple, but due to the complexity of multiphase flow, its theoretical model has not been fully established yet.

^{[4]}In addition, the pumps must be able to cope with multiphase flows to a certain extent.

^{[5]}A particularly challenging phenomenon that emerges from these couplings is the transition from fluid invasion to fracturing during multiphase flow.

^{[6]}Our research exploited this to model the multiphase flow through an anisotropic permeability medium and its effect on the oil recovery.

^{[7]}Multiphase flow is solved using the Volume-Of-Fluid method, and the transport of species is solved using the continuous species transfer method.

^{[8]}From the other side, this makes inevitable the development of simplified methods with improved computational performance like, for instance, the so-called vertically integrated (VI) models based on partial integration of the system of multiphase flow and energy equations.

^{[9]}Conventionally, the used of simplistic models most of times do not allow seeing phenomena in the adequate resolution (near wellbore and porous media effects, multiphase flow in pipelines, etc.

^{[10]}Multiphase flows management is a major challenge in many space applications given the different gravity levels involved.

^{[11]}Multiphase flow is a prevalent topic in many disciplines, and flow regime identification is an essential foundation in multiphase flow research.

^{[12]}The proposed model also establishes mercury cyclic porosimetry as a standard experimental procedure for measuring α, which can then be used in continuum models of porous media where connectivity effects play a significant role, such as in multiphase flow.

^{[13]}The structure of the vortex was identify and some solutions were analysed to prevent or reduce the size of multiphase flow.

^{[14]}A numerical method for the simulation of multiphase flows with phase change on unstructured grids is presented.

^{[15]}Such a phenomenon has crucial consequences for multiphase flows in which confined nano- and/or picolitre droplets are considered.

^{[16]}Aiming at addressing the key concerns about flow fronts and air bubble entrapment, the present study proposes a modelling framework of the multiphase flow of resin and air in a dual scale porous medium, i.

^{[17]}Steel production represents a complex process which is accompanied by a series of physical–chemical processes from melting, through the multiphase flow of steel and chemical reactions (processes taking place between the slag, metal, and an inert gas) after solidification [.

^{[18]}At the same time, mineral reactions, asphaltene deposition, and CO2 pressurization will cause the change of porous media geometry, which will affect the multiphase flow.

^{[19]}A venturi device is commonly used as an integral part of a multiphase flowmeter (MPFM) in real-time oil-gas production monitoring.

^{[20]}Recently, we have suggested that the combination of multiphase flow and variable operating conditions could create similar reservoir signatures (as quantified using classic flow-regime identification techniques).

^{[21]}As a fast and nonintrusive measurement and visualization technique, electrical capacitance tomography (ECT) is rapidly expanding its applications in the research on multiphase flow, fluidization, drying, combustion, and so on.

^{[22]}In this talk, we will present recent efforts to develop and apply a range of laser-based and other combined diagnostic techniques to a number of multiphase flows, both isothermal and in the presence of heat transfer, and extending to phase change processes (boiling and freezing).

^{[23]}The influence of the fractional composition of mechanical impurities contained in oil on erosion–corrosion processes in infield pipelines was investigated taking into account the hydrodynamics of multiphase flows.

^{[24]}The energy balance approach includes pressure losses in the slide-gate, wall friction, and nozzle geometry variations, including the effects of multiphase flow due to argon gas injection.

^{[25]}This discovery has broad relevance in areas such as froth flotation, liquid-infused surfaces, multiphase flows and microfluidics.

^{[26]}At these conditions, the relative permeability concept applies to take into account the multiphase flow.

^{[27]}A crucial parameter for studying erosion in multiphase flows is the flow pattern.

^{[28]}The technique exhibits uncertainties of ±2K in temperature and 2% in capturing the correct scattering profile, showing its potential utility for probing liquid temperature distributions in multiphase flows.

^{[29]}Conservation equations for mass, momentum, and energy for multiphase flow are derived using the Reynolds transport theorem.

^{[30]}Yet their evolution during hydrate formation and decomposition is complicated which couples phase transition, multiphase flow and component migration; relating knowledge still remain limited.

^{[31]}Recent advances in X-ray microtomography (micro-CT) technology have enabled investigations of multiphase flow through natural porous media at the pore scale.

^{[32]}

## computational fluid dynamic

To investigate the mechanism of the effect of process parameters on bubble flow behavior during automated fiber placement (AFP) and the relationship between the bubble and voids, mechanical properties of laminates, this paper analyzes the multiphase flow coupling behavior of the bubble and fiber formation using computational fluid dynamics (CFD) and finite element (FE) method under different AFP process parameters.^{[1]}Computational fluid dynamics (CFD) and computational multiphase fluid dynamics (CMFD) methods have attracted great attentions in predicting single-phase and multiphase flows under steady-state or transient conditions in the field of nuclear reactor engineering.

^{[2]}Detailed computational fluid dynamic simulations with multiphase flow models reveal benefits of adding small amounts of H2O2 in the feed stream of the ultrasonic cleaner; this practice causes larger droplets with shorter residence times inside the clinic before settling down or escaping through air vents.

^{[3]}Computational Fluid Dynamics (CFD) is widely used as a numerical technique in handling complex multiphase flow problems in different operational conditions.

^{[4]}Taking the spillway of a reservoir as the research object, the numerical model of erosion wear caused by sediment-laden particle flows on the spillway was established by using the computational fluid dynamics (CFD) method, VOF (Volume of Fluid) multiphase flow model and DPM (Discrete Phase Model).

^{[5]}This paper focuses on the investigation of a multiphase flow of water, air, and abrasive particles inside and at the outlet of the abrasive head with the help of computational fluid dynamics calculations and measurements.

^{[6]}The discrete elements method (DEM) coupled with computational fluid dynamics (CFD) is widely employed in the numerical simulation of a multiphase flow including solid particles.

^{[7]}Simulations of two-phase (air and water) flow in a pipe are very relevant topics; however, with the increased understanding of multiphase flow in pipes, the application of computational fluid dynamics (CFD) in other complex flow geometries involved in oil & gas industries are becoming more common.

^{[8]}In this paper, 3D computational fluid dynamics (CFD) modeling is used to analyze transient multiphase flow and inclusion removal in a gas-stirred ladle.

^{[9]}In this research, a Graphical Processing Unit (GPU) accelerated Discrete Element Method (DEM) code was developed and coupled with the Computational Fluid Dynamic (CFD) software MFiX to simulate granular and multiphase flows.

^{[10]}The computational approach utilizes the Euler-Eulerian multiphase flow model based on the solid kinetic theory in a 3D Computational Fluid Dynamics (CFD) framework.

^{[11]}The multiphase flow characteristics during low-pressure plasma spraying using ceramic nano-agglomerated powders at different chamber pressures are studied via computational fluid dynamics modelling and experiment.

^{[12]}This paper reports the results from a series of multiphase flow (slide material and the ambient seawater) numerical simulations using a computational fluid dynamics (CFD) approach aimed at investigating the vertical forces during submarine slide flow around a pipeline at different gap ratios (pipeline-seabed gap normalized by pipeline diameter) from 0.

^{[13]}With the aim to set and validate a computational fluid dynamic (CFD) multiphase flow simulation model based on the MFiX suite – as a support for the design and optimization of advanced reactors for energy purposes – a wide experimental campaign has been carried out with cypress (Cupressus sempervirens) wood chips in a lab-scale bubbling fluidized-bed gasification unit in different operation modes: pyrolysis, air-blown gasification as well as steam gasification of char.

^{[14]}In order to clearly know the multiphase flow characteristics, a FR prototype is designed and the gas-solid hydrodynamics in FR are investigated using computational fluid dynamic (CFD) method.

^{[15]}Computational fluid dynamics (CFD) is a powerful tool for prediction and analysis of complex multiphase flow hydrodynamics and residence time distribution (RTD) in chemical reactors.

^{[16]}Currently, Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) has become a powerful tool for the study of multiphase flows.

^{[17]}The flow inside the injector was considered as multiphase flow and was calculated through unsteady Computational Fluid Dynamics simulations using a Eulerian–Eulerian two-fluid approach.

^{[18]}This study investigates the effects of elbow on the transition and development of multiphase flow using computational fluid dynamics modelling techniques.

^{[19]}This paper used the conventional computational fluid dynamics analysis software STAR-CCM+, the models such as VOF multiphase flow model, 6DOF kinematics model and RNG k-ε turbulence model combined with RANS numerical method were used to simulate the coupling of the ship-induced wave in head-on situation in the inland river shallow channel based on CFD technology.

^{[20]}Computational fluid dynamics (CFD), therefore, has been widely used to model multiphase flow in stirred‐tank bioreactors to minimize the number of optimization experiments.

^{[21]}The National Energy Technology Laboratory (NETL) has been applying non-intrusive UQ methodologies to categorize and quantify uncertainties in computational fluid dynamics (CFD) simulations of gas-solid multiphase flows.

^{[22]}

## two phase flow

The accuracy of the overall two-phase flow model is investigated using the commercial multiphase flow dynamic code OLGA.^{[1]}These investigations can help to better understand the two-phase flow and bubble detachment mechanism, and provide a foundation for electrochemical reaction, multiphase flow studies and optimize the design of gas diffusion layers and flow fields for PEMECs in the future.

^{[2]}In low field NMR multiphase flow measurement, the magnetization time and magnetization length are affected by the two-phase flow velocity and water fraction, so it is difficult to realize the complete magnetization of multiphase flow with fixed length magnet.

^{[3]}The two-phase flow is part of a multiphase flow, where the flow can consist of gas/vapor and liquid phases, which flow simultaneously.

^{[4]}To identify conveniently multiphase flow regimes in subsea pipeline-risers, we study in this paper experimentally two-phase flows in a 1657 m long pipeline with an S-shaped riser to simulate field experiment, within a wide range of gas and liquid velocities.

^{[5]}This paper is devoted to deriving several fractional-order models for multiphase flows in porous media, focusing on some special cases of the two-phase flow.

^{[6]}The two-phase flow regime in electrode is simulated via a multicomponent multiphase flow model to reconstruct the liquid water morphologies.

^{[7]}In the field of petroleum multiphase flow research, accurate measurement of oil-gas two-phase flow parameters is the research focus.

^{[8]}The Volume of Fluid (VOF) multiphase flow modeling method embodied in ANSYS Fluent was applied to simulate the Newtonian oil/non-Newtonian foam two-phase flow.

^{[9]}In this study, to achieve effective control of the downhole pressure to ensure safety, a gas–liquid two-phase flow model based on the drift flux model is developed to describe the characteristics of transient multiphase flow in the wellbore.

^{[10]}

## enhanced oil recovery

Displacement efficiency and displacement pattern of multiphase flow in porous media have a profound influence on many geo-energy applications such as geologic CO$_{2}$ sequestration and enhanced oil recovery.^{[1]}Mathematical solutions for multiphase flow in porous medium are key for determining relative permeability curves from laboratory data, to check numerical reservoir simulation results and for screening an enhanced oil recovery technique.

^{[2]}: Accurate characterization of surface roughness and understanding its influence on multiphase flow behavior are important for industrial and environmental applications such as enhanced oil recovery, CO2 geological sequestration, and remediation of contaminated aquifers.

^{[3]}Two-phase and three-phase equilibria are frequently encountered in a variety of industrial processes, such as carbon dioxide (CO2) injection for enhanced oil recovery in oil reservoirs, multiphase separation in surface separators, and multiphase flow in wellbores and pipelines.

^{[4]}Because of complex chemical reactions and multiphase flow physics, the displacement front stability for in-situ combustion (ISC) enhanced oil recovery (EOR) processes are not well understood.

^{[5]}This unexpected result that sweep does not necessarily increase with wettability has major implications to enhanced oil recovery and suggests that the dynamics of multiphase flow in porous media has a complex relationship with the geometry of the medium and the hydrodynamical parameters.

^{[6]}The correlations are computationally efficient and reliable, and they are primarily designed for incorporation into a multiphase flow simulator for geology- and energy-related applications including CO2 sequestration, CO2-enhanced geothermal systems, and CO2-enhanced oil recovery.

^{[7]}This presentation will discuss several advances and applications of silica-based nanofluids in chemical enhanced oil recovery (EOR) processes related to interfacial phenomena in multiphase systems and physics of multiphase flow in porous media, and in particular the oil recovery characteristics resulting from nanofluids based low-salinity water flooding and chemical EOR processes.

^{[8]}

## liquid two phase

To study the effect of fine particle size and volume concentration on the performance of solid-liquid two-phase centrifugal pump, the mixture multiphase flow model, RNG k-e turbulence model, and SIMPLEC algorithm were used to simulate the two-phase flow of the centrifugal pump.^{[1]}According to the data of multiphase flow experimental loop, the influence of liquid viscosity and the instantaneous volume flow rate change of gas-liquid two-phase on the transition criterion is analyzed.

^{[2]}The degradation characteristics of oily sludge in the bioreactor were studied by using Euler-multiphase flow method, in which the gas-liquid two-phase and gas-liquid-solid three-phase flow field dynamics model was established.

^{[3]}

## single phase flow

Following our previous work [Energies, 11: 1798, 2018] on REV size for single-phase flow, this work considers the critical size of REV for multiphase flow in porous media.^{[1]}Pressure traverse in multiphase flow differs from single phase flow due to the differential flow rates of the different phases.

^{[2]}We demonstrate that MGR, guided by physics and theory in block preconditioning, can tackle several distinct and challenging problems, notably: a hybrid discretization of single-phase flow, compositional multiphase flow with complex wells, and hydraulic fracturing simulations.

^{[3]}

## oil gas water

Subgraphs are used to yield partitions of the flow unit domain and marker functions similar to phase indicator functions commonly found in multiphase flow modeling are implemented to label flow units intersecting gas-oil, gas-water, or oil-water contacts.^{[1]}The phenomenon of oil-gas-water multiphase flow is common in oil Wells in the middle and late stage of oil field development.

^{[2]}In this study, a new method for gas holdup measurement in water continuous oil-gas-water multiphase flow based on conductance sensors is proposed.

^{[3]}

## gamma ray densitometry

This paper presents a novel methodology for volume fraction predictions in multiphase flow meters in offshore petroleum industries using gamma-ray densitometry.^{[1]}A novel non-invasive measurement technique using continuous-wave Doppler ultrasound (CWDU) and bandpass power spectral density (BPSD) is proposed for multiphase flow applications and compared with the more established gamma-ray densitometry measurement.

^{[2]}This study presents a method based on gamma-ray densitometry using only one multilayer perceptron artificial neural network (ANN) to identify flow regime and predict volume fraction of gas, water, and oil in multiphase flow, simultaneously, making the prediction independent of the flow regime.

^{[3]}

## high water cut

When oil fields reach the high water-cut stage or in late development, the multiphase flow of oil/gas or oil/water, even oil/gas/water will occur in a reservoir.^{[1]}As more and more oil fields enter the high water-cut stage, it is of great significance to develop low-cost multiphase flow meters (MPFMs) for high water-cut flows.

^{[2]}

## Complex Multiphase Flow

This study can be considered as a step forward in discrete modeling of drying of capillary porous media with 3D secondary capillary structures and should be of interest for various applications in the field of complex multiphase flow phenomena in porous media.^{[1]}The study aims to improve understanding of the interaction between the physical parameters involved in complex multiphase flow in porous media (e.

^{[2]}Besides, the computation load of current model is small due to no solution of complex multiphase flow.

^{[3]}Computational Fluid Dynamics (CFD) is widely used as a numerical technique in handling complex multiphase flow problems in different operational conditions.

^{[4]}The dynamic time-frequency response, field test results, and actual laboratory results are consistent, verifying the effectiveness of the method proposed in this paper and further providing a theory for improving the effectiveness of the sand production monitoring method under complex multiphase flow conditions.

^{[5]}Overall, this study provides an innovative approach for PIV measurement of complex multiphase flow field, and a useful reference for appropriate numerical models selection.

^{[6]}Traditionally, numerous compromises or simplifications must be made when simulating complex multiphase flows and their transitions within production and separation systems using CFD.

^{[7]}Computational fluid dynamics (CFD) is a powerful tool for prediction and analysis of complex multiphase flow hydrodynamics and residence time distribution (RTD) in chemical reactors.

^{[8]}The interplay between shock heating, dynamical instabilities, turbulence, and radiative heating and cooling creates a complex multiphase flow with a rain-like morphology.

^{[9]}

## Water Multiphase Flow

In this study, an investigation of sand transport in heavy-oil/water multiphase flow is performed.^{[1]}This paper provides a numerical model, coupled with reservoir sand-gas-water multiphase flow processes, which is capable to simulate the process of sand production in natural gas hydrate reservoirs.

^{[2]}Researches about flow pattern of oil-water multiphase flow pipes are mainly about straight pipelines, but few about elbows.

^{[3]}The phenomenon of oil-gas-water multiphase flow is common in oil Wells in the middle and late stage of oil field development.

^{[4]}Aiming at the problem of on-line measurement of the flow of oil, gas and water multiphase flow in the production process of oil and gas wells, a set of real-time flow monitoring system based on STM32 and Lora was designed.

^{[5]}In this study, a new method for gas holdup measurement in water continuous oil-gas-water multiphase flow based on conductance sensors is proposed.

^{[6]}To account for the differences between hydrate saturation and hydrate pore habit, we performed a gas-water multiphase flow simulation that combines the fluids’ fundamental properties (density ratio, viscosity ratio, and wettability).

^{[7]}The correlation predictions were compared to experimental data in which the root mean square errors of the oil-air-water multiphase flow prediction results are 7.

^{[8]}

## Eulerian Multiphase Flow

Based on the Eulerian multiphase flow model and RNG k−ε turbulence model, the CFD model is established for the simulation research.^{[1]}A centrifugal slurry pump was analyzed using the particle Eulerian-Eulerian multiphase flow model to study the impeller wear.

^{[2]}Through Fluent, this paper investigated the pyrolysis preparation of CeO2 with the addition of citric acid by adopting the Eulerian multiphase flow model, component transportation model, and standard k-ε turbulence model.

^{[3]}The computational approach utilizes the Euler-Eulerian multiphase flow model based on the solid kinetic theory in a 3D Computational Fluid Dynamics (CFD) framework.

^{[4]}To control the dust emissions and reduce the mass ratio of the dust into the press device of the granulator, an Eulerian multiphase flow model was first used to analyze the effects of the storage cage structure, flow velocity at the duct outlet, ambient wind speed and particle size on dust emissions.

^{[5]}In this study, the two-fluid Eulerian–Eulerian multiphase flow model in ANSYS Fluent (v17.

^{[6]}

## Transient Multiphase Flow

Based on those research findings, the two-phase LBM can be demonstrated to be a powerful tool for investigating dynamic nonequilibrium effects for transient multiphase flow in porous media from the microscale to the REV scale.^{[1]}The aim of this work is to investigate the effect of nitrogen injection flow rate and pressure on unloading frac hits gas wells in transient multiphase flow.

^{[2]}In this paper, 3D computational fluid dynamics (CFD) modeling is used to analyze transient multiphase flow and inclusion removal in a gas-stirred ladle.

^{[3]}Transient multiphase flow simulations represent the state of the art in the prediction and analysis of slugging behavior in multiphase transport pipelines (both terrain-induced and hydrodynamic slugging).

^{[4]}To investigate the transient multiphase flow, slag entrainment and exposed slag eye in the mold with EMBr and argon injection, a transient multiphase LES model was constructed.

^{[5]}In this study, to achieve effective control of the downhole pressure to ensure safety, a gas–liquid two-phase flow model based on the drift flux model is developed to describe the characteristics of transient multiphase flow in the wellbore.

^{[6]}

## Liquid Multiphase Flow

The predictive simulation of gas–liquid multiphase flows at industrial scales reveals the challenging task to consider turbulence and interfacial structures, which span a large range of length scales.^{[1]}The atomization mechan