32,729 research outputs found
Experimental Validation of Multiphase Flow Models and Testing of Multiphase Flow Meters: A Critical Review of Flow Loops Worldwide
Around the world, research into multiphase flow is performed by scientists with hugely diverse backgrounds: physicists, mathematicians and engineers from mechanical, nuclear, chemical, civil, petroleum, environmental and aerospace disciplines. Multiphase flow models are required to investigate the co-current or counter-current flow of different fluid phases under a wide range of pressure and temperature conditions and in several different configurations. To compliment this theoretical effort, measurements at controlled experimental conditions are required to verify multiphase flow models and assess their range of applicability, which has given rise to a large number of multiphase flow loops around the world. These flow loops are also used intensively to test and validate multiphase flow meters, which are devices for the in-line measurement of multiphase flow streams without separation of the phases. However, there are numerous multiphase flow varieties due to differences in pressure and temperature, fluids, flow regimes, pipe geometry, inclination and diameter, so a flow loop cannot represent all possible situations. Even when experiments in a given flow loop are believed to be sufficiently exhaustive for a specific study area, the real conditions encountered in the field tend to be very different from those recreated in the research facility. This paper presents a critical review of multiphase flow loops around the world, highlighting the pros and cons of each facility with regard to reproducing and monitoring different multiphase flow situations. The authors suggest a way forward for new developments in this area
Experimental validation of multiphase flow models and testing of multiphase flow meters: A critical review of flow loops worldwide
Around the world, research into multiphase flow is performed by scientists with
hugely diverse backgrounds: physicists, mathematicians and engineers from
mechanical, nuclear, chemical, civil, petroleum, environmental and aerospace
disciplines. Multiphase flow models are required to investigate the co-current or
counter-current flow of different fluid phases under a wide range of pressure and
temperature conditions and in several different configurations. To compliment
this theoretical effort, measurements at controlled experimental conditions are
required to verify multiphase flow models and assess their range of applicability,
which has given rise to a large number of multiphase flow loops around the
world. These flow loops are also used intensively to test and validate multiphase
flow meters, which are devices for the in-line measurement of multiphase flow
streams without separation of the phases. However, there are numerous
multiphase flow varieties due to differences in pressure and temperature, fluids,
flow regimes, pipe geometry, inclination and diameter, so a flow loop cannot
represent all possible situations. Even when experiments in a given flow loop are
believed to be sufficiently exhaustive for a specific study area, the real
conditions encountered in the field tend to be very different from those recreated
in the research facility. This paper presents a critical review of multiphase flow
loops around the world, highlighting the pros and cons of each facility with
regard to reproducing and monitoring different multiphase flow situations. The
authors suggest a way forward for new developments in this area
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A High Performance Lattice Boltzmann Solver with Applications to Multiphase Flow in Porous Media
Multiphase flow is significant to many industrial processes such as the geologic storage of CO2 and oil recovery. Microscale simulation of flow in complex geological formations such as saline aquifers or oilfields is a complex and challenging task. The main goal of our study is to overcome high computational demand of multiphase flow simulations by using high performance computing. To model multiphase flow in porous media, we used a multiphase flow lattice Boltzmann (LB) method, which is recognized as an alternative to the classical computational fluid dynamics (CFD) methods. The developed LB model used an extended Color-Gradient approach with improved numerical stability, and it can be used to compute multiphase flow simulations with low capillary number and high viscosity ratios. To optimize computational efficiency, we apply the LB model to a parallel scheme written in C++ using the Message Passing Interface (MPI). Highly parallel runs of these simulations were performed using the HPC system at the Texas Advanced Computing Center at the University of Texas at Austin. We herein introduce the capability of our tool for multiphase flow simulation in porous media and present its application to CO2 sequestration in geological formations. The model has been applied to the simulation of CO2 and brine in sandstone rocks, by employing three-dimensional micro-CT images of rock samples. Injection of supercritical CO2 into the brine-saturated rock samples is simulated and complex displacement patterns under various reservoir conditions are identified.Texas Advanced Computing Center (TACC
Three-Dimensional Multi-Relaxation Time (MRT) Lattice-Boltzmann Models for Multiphase Flow
In this paper, three-dimensional (3D) multi-relaxation time (MRT)
lattice-Boltzmann (LB) models for multiphase flow are presented. In contrast to
the Bhatnagar-Gross-Krook (BGK) model, a widely employed kinetic model, in MRT
models the rates of relaxation processes owing to collisions of particle
populations may be independently adjusted. As a result, the MRT models offer a
significant improvement in numerical stability of the LB method for simulating
fluids with lower viscosities. We show through the Chapman-Enskog multiscale
analysis that the continuum limit behavior of 3D MRT LB models corresponds to
that of the macroscopic dynamical equations for multiphase flow. We extend the
3D MRT LB models developed to represent multiphase flow with reduced
compressibility effects. The multiphase models are evaluated by verifying the
Laplace-Young relation for static drops and the frequency of oscillations of
drops. The results show satisfactory agreement with available data and
significant gains in numerical stability.Comment: Accepted for publication in the Journal of Computational Physic
Measurement and analysis of water/oil multiphase flow using electrical capacitance tomography sensor
The paper investigates the capability of using a portable 16-segmented Electrical Capacitance Tomo-graphy (ECT) sensor and a new excitation technique to measure the concentration profile of water/oil multiphase flow. The concentration profile obtained from the capacitance measurements is capable of providing images of the water and oil flow in the pipeline. The visualization results deliver information regarding the flow regime and concentration distribution of the multiphase flow. The information is able to help in designing process equipment and verifying the existing computational modeling and simu-lation techniques
Three dimensional hysdrodynamic lattice-gas simulations of binary immiscible and ternary amphiphilic flow through porous media
We report the results of a study of multiphase flow in porous media. A
Darcy's law for steady multiphase flow was investigated for both binary and
ternary amphiphilic flow. Linear flux-forcing relationships satisfying Onsager
reciprocity were shown to be a good approximation of the simulation data. The
dependence of the relative permeability coefficients on water saturation was
investigated and showed good qualitative agreement with experimental data.
Non-steady state invasion flows were investigated, with particular interest in
the asymptotic residual oil saturation. The addition of surfactant to the
invasive fluid was shown to significantly reduce the residual oil saturation.Comment: To appear in Phys. Rev.
On a model of multiphase flow
We consider a hyperbolic system of three conservation laws in one space
variable. The system is a model for fluid flow allowing phase transitions; in
this case the state variables are the specific volume, the velocity and the
mass density fraction of the vapor in the fluid. For a class of initial data
having large total variation we prove the global existence of solutions to the
Cauchy problem.Comment: 32 pages. Revised and corrected versio
Oscillatory multiphase flow strategy for chemistry and biology
Continuous multiphase flow strategies are commonly employed for high-throughput parameter screening of physical, chemical, and biological processes as well as continuous preparation of a wide range of fine chemicals and micro/nano particles with processing times up to 10 min. The inter-dependency of mixing and residence times, and their direct correlation with reactor length have limited the adaptation of multiphase flow strategies for studies of processes with relatively long processing times (0.5–24 h). In this frontier article, we describe an oscillatory multiphase flow strategy to decouple mixing and residence times and enable investigation of longer timescale experiments than typically feasible with conventional continuous multiphase flow approaches. We review current oscillatory multiphase flow technologies, provide an overview of the advancements of this relatively new strategy in chemistry and biology, and close with a perspective on future opportunities.Natural Sciences and Engineering Research Council of Canada (Postgraduate Fellowship
Fluctuation-induced dynamics of multiphase liquid jets with ultra-low interfacial tension
Control of fluid dynamics at the micrometer scale is essential to emulsion
science and materials design, which is ubiquitous in everyday life and is
frequently encountered in industrial applications. Most studies on multiphase
flow focus on oil-water systems with substantial interfacial tension. Advances
in microfluidics have enabled the study of multiphase flow with more complex
dynamics. Here, we show that the evolution of the interface in a jet surrounded
by a co-flowing continuous phase with an ultra-low interfacial tension presents
new opportunities to the control of flow morphologies. The introduction of a
harmonic perturbation to the dispersed phase leads to the formation of
interfaces with unique shapes. The periodic structures can be tuned by
controlling the fluid flow rates and the input perturbation; this demonstrates
the importance of the inertial effects in flow control at ultra-low interfacial
tension. Our work provides new insights into microfluidic flows at ultra-low
interfacial tension and their potential applications
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