9,584 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
A Force-Balanced Control Volume Finite Element Method for Multi-Phase Porous Media Flow Modelling
Dr D. Pavlidis would like to acknowledge the support from the following research grants: Innovate UK ‘Octopus’, EPSRC ‘Reactor Core-Structure Re-location Modelling for Severe Nuclear Accidents’) and Horizon 2020 ‘In-Vessel Melt Retention’. Funding for Dr P. Salinas from ExxonMobil is gratefully acknowledged. Dr Z. Xie is supported by EPSRC ‘Multi-Scale Exploration of Multi-phase Physics in Flows’. Part funding for Prof Jackson under the TOTAL Chairs programme at Imperial College is also acknowledged. The authors would also like to acknowledge Mr Y. Debbabi for supplying analytic solutions.Peer reviewedPublisher PD
Central Schemes for Porous Media Flows
We are concerned with central differencing schemes for solving scalar
hyperbolic conservation laws arising in the simulation of multiphase flows in
heterogeneous porous media. We compare the Kurganov-Tadmor, 2000 semi-discrete
central scheme with the Nessyahu-Tadmor, 1990 central scheme. The KT scheme
uses more precise information about the local speeds of propagation together
with integration over nonuniform control volumes, which contain the Riemann
fans. These methods can accurately resolve sharp fronts in the fluid
saturations without introducing spurious oscillations or excessive numerical
diffusion. We first discuss the coupling of these methods with velocity fields
approximated by mixed finite elements. Then, numerical simulations are
presented for two-phase, two-dimensional flow problems in multi-scale
heterogeneous petroleum reservoirs. We find the KT scheme to be considerably
less diffusive, particularly in the presence of high permeability flow
channels, which lead to strong restrictions on the time step selection;
however, the KT scheme may produce incorrect boundary behavior
Comparison of multiphase SPH and LBM approaches for the simulation of intermittent flows
Smoothed Particle Hydrodynamics (SPH) and Lattice Boltzmann Method (LBM) are
increasingly popular and attractive methods that propose efficient multiphase
formulations, each one with its own strengths and weaknesses. In this context,
when it comes to study a given multi-fluid problem, it is helpful to rely on a
quantitative comparison to decide which approach should be used and in which
context. In particular, the simulation of intermittent two-phase flows in pipes
such as slug flows is a complex problem involving moving and intersecting
interfaces for which both SPH and LBM could be considered. It is a problem of
interest in petroleum applications since the formation of slug flows that can
occur in submarine pipelines connecting the wells to the production facility
can cause undesired behaviors with hazardous consequences. In this work, we
compare SPH and LBM multiphase formulations where surface tension effects are
modeled respectively using the continuum surface force and the color gradient
approaches on a collection of standard test cases, and on the simulation of
intermittent flows in 2D. This paper aims to highlight the contributions and
limitations of SPH and LBM when applied to these problems. First, we compare
our implementations on static bubble problems with different density and
viscosity ratios. Then, we focus on gravity driven simulations of slug flows in
pipes for several Reynolds numbers. Finally, we conclude with simulations of
slug flows with inlet/outlet boundary conditions. According to the results
presented in this study, we confirm that the SPH approach is more robust and
versatile whereas the LBM formulation is more accurate and faster
New non-equilibrium matrix imbibition equation for Kondaurov's double porosity model
The paper deals with the global Kondaurov double porosity model describing a
non-equilibrium two-phase immiscible flow in fractured-porous reservoirs when
non-equilibrium phenomena occur in the matrix blocks, only. It is shown that
the homogenized model can be represented as usual equations of two-phase
incompressible immiscible flow, except for the addition of two source terms
calculated by a solution to a local problem which is a boundary value problem
for a non-equilibrium imbibition equation given in terms of the real saturation
and a non-equilibrium parameter.Comment: 11 pages, 1 figur
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