Transition Process to Turbulent Flow in Porous Media

2005 ◽  
Author(s):  
Y. Takatsu ◽  
T. Masuoka
Keyword(s):  
Porous Media ◽  
Flow Field ◽  
Turbulence Models ◽  
Flow In Porous Media ◽  
Solid Matrix ◽  
Theoretical Argument ◽  
Transition Flow ◽  
Transition Flow Regime ◽  
Flow Through ◽  
Microscopic Flow

Turbulence in porous media has attracted much interest recently, and many turbulence models have been proposed [1-12]. However, the mathematical treatments in some turbulence models have been developed without reference to the unique structure of vortices in porous media. The further development of the turbulence model and the theoretical argument in the transition flow regime need the experimental verification of the microscopic flow field in porous media, but the geometric complexity of porous media brings about technical difficulties of the measurement and the visualization. Therefore, we adopt the flow through a bank of cylinders in a narrow gap as a model for the flow through porous media, and perform the PIV (Particle Image Velocimetry) and LIF (Laser Induced Fluorescence) techniques to examine the microscopic flow field in porous media. We have confirmed that the solid matrix in porous media plays an important role in the vortex diffusion. The large vorticity at the throat produces such vortex as the swirl flow. On the other hand, the obstruction due to the solid matrix forces such large vortex as a Ka´rma´n vortex to be dissipative. Furthermore, the present experimental results are in agreement with our model [2] for the production and dissipation of turbulence.

Flow Characteristics at Low Quality for Horizontal Gas-Liquid Two-Phase Flow Through Porous Media

2007 ◽  
Author(s):  
Yasuyuki Takatsu ◽  
Takashi Masuoka ◽  
Takeru Takehara
Keyword(s):  
Porous Media ◽  
Flow Field ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Solid Matrix ◽  
Phase Flow ◽  
Flow Through Porous Media ◽  
Two Phase ◽  
Flow Through ◽  
Microscopic Flow

As the geometric complexity of porous media brings about technical diffculties of the measurement and the visualization of the microscopic flow field, only few attempts have ever been made at the experimental examination of the two-phase flow through porous media. Therefore, we adopt a bank of tubes in a narrow gap as a porous model, and perform the visualization to examine the microscopic flow field for the horizontal two-phase flow through porous media in detail. The solid matrix in porous media plays an important role in the formation of the two-phase flow pattern. The solid matrix forces larger bubble than its representative length to be split, and the liquid bridge due to the capillary effect prevents the gas-phase merging together. Furthermore, the bubbles are trapped in the wide space surrounded with the solid matrices, where the compound bubble further absorbs smaller bubbles.

A Mechanistic Explanation of Channels in Debris Beds

1986 ◽  
Vol 108 (1) ◽  
pp. 125-131 ◽  
Author(s):  
A. W. Reed
Keyword(s):  
Porous Media ◽  
Mechanistic Explanation ◽  
Flow In Porous Media ◽  
Spherical Particles ◽  
Solid Matrix ◽  
Saturation Curve ◽  
Two Phase ◽  
Flow Equations ◽  
Free Body ◽  
Particulate Debris

A mechanistic explanation of channeling during boiling in unconsolidated particulate debris beds is formulated by combining a free-body force diagram and the capillary pressure-saturation curve for porous media. The model is consistent with the principles of two-phase flow in porous media and provides boundary conditions for the flow equations in the unchanneled region. Experimental evidence for spherical particles presented here implies that the solid matrix in the channeled region cannot maintain a shear force and therefore behaves like a fluid without being fluidized in the classical sense.

Numerical Investigation of the “Poor Man’s Navier–Stokes Equations” with Darcy and Forchheimer Terms

2016 ◽  
Vol 26 (05) ◽  
pp. 1650086
Author(s):  
Tingting Tang ◽  
Zhiyong Li ◽  
J. M. McDonough ◽  
P. D. Hislop
Keyword(s):  
Porous Media ◽  
Numerical Investigation ◽  
Stokes Equations ◽  
Discrete Dynamical System ◽  
Flow In Porous Media ◽  
Phase Portraits ◽  
Navier Stokes ◽  
Flow Through Porous Media ◽  
Navier Stokes Equations ◽  
Flow Through

In this paper, a discrete dynamical system (DDS) is derived from the generalized Navier–Stokes equations for incompressible flow in porous media via a Galerkin procedure. The main difference from the previously studied poor man’s Navier–Stokes equations is the addition of forcing terms accounting for linear and nonlinear drag forces of the medium — Darcy and Forchheimer terms. A detailed numerical investigation focusing on the bifurcation parameters due to these additional terms is provided in the form of regime maps, time series, power spectra, phase portraits and basins of attraction, which indicate system behaviors in agreement with expected physical fluid flow through porous media. As concluded from the previous studies, this DDS can be employed in subgrid-scale models of synthetic-velocity form for large-eddy simulation of turbulent flow through porous media.

A General Macroscopic Model for Turbulent Flow in Porous Media

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Nima F. Jouybari ◽  
Mehdi Maerefat ◽  
T. Staffan Lundström ◽  
Majid E. Nimvari ◽  
Zahra Gholami
Keyword(s):  
Porous Media ◽  
Turbulent Flow ◽  
Present Model ◽  
Flow Characteristics ◽  
Flow In Porous Media ◽  
Macroscopic Model ◽  
Solid Matrix ◽  
Turbulent Regime ◽  
Rod Bundles ◽  
Capillary Model

The present study deals with the generalization of a macroscopic turbulence model in porous media using a capillary model. The additional source terms associated with the production and dissipation of turbulent kinetic energy due to the presence of solid matrix are calculated using the capillary model. The present model does not require any prior pore scale simulation of turbulent flow in a specific porous geometry in order to close the macroscopic turbulence equations. Validation of the results in packed beds, periodic arrangement of square cylinders, synthetic foams, and longitudinal flows such as pipes, channels, and rod bundles against available data in the literature reveals the ability of the present model in predicting turbulent flow characteristics in different types of porous media. Transition to the fully turbulent regime in porous media and different approaches to treat this phenomenon are also discussed in the present study. Finally, the general model is modified so that it can be applied to lower Reynolds numbers below the range of fully turbulent regime in porous media.

Prediction of Local Losses of Low Re Flows in Elastic Porous Media

2017 ◽  
Author(s):  
Sid M. Becker ◽  
Stefan Gasow
Keyword(s):  
Porous Media ◽  
Flow Field ◽  
Stokes Equations ◽  
Applied Pressure ◽  
Porous Matrix ◽  
Pore Geometry ◽  
Test Case ◽  
Hydraulic Permeability ◽  
Local Pressure ◽  
Flow Through

An isotropic elastic porous structure whose pore geometry is regular (periodically uniform) will experience non-uniform deformation when a viscous fluid flows through the matrix under the influence of an externally applied pressure difference. In such a case, the flow field will experience a non-uniform pressure gradient whose magnitude increases in the direction of bulk flow. In this study, a method is presented that predicts local losses of the flow through a porous matrix whose geometry varies in the direction of flow. Employing an asymptotic expansion about the variation in geometry provides an expression relating local hydraulic permeability to local pore geometry. In this way the pressure field is able to be determined without requiring the explicit solution of the flow field. In this study a test case is presented showing that the local pressure losses are predicted to be within 0.5% of the losses determined from the solution to the Navier-Stokes Equations. The approach can be used to simplify the coupled fluid-solid problem of flow through elastic porous media by replacing the need to explicitly solve the flow field.

Studies on Foam Flow in the Porous Media in the Last Decade: A Review

2012 ◽  
Vol 616-618 ◽  
pp. 257-262 ◽  
Author(s):  
Ming Ming Lv ◽  
Shu Zhong Wang ◽  
Ze Feng Jing ◽  
Ming Luo
Keyword(s):  
Porous Media ◽  
Oil Recovery ◽  
Flow In Porous Media ◽  
Balance Model ◽  
Sweep Efficiency ◽  
Foam Flow ◽  
New Findings ◽  
X Ray Computed ◽  
Flow Through

Foam has been used for several decades to decrease the mobility of drive gas or steam, thereby increasing the reservoir sweep efficiency and enhancing the oil recovery. The optimization of the operations requires a thorough understanding of the physical aspects involved in foam flow through porous media. The present paper aims mainly at reviewing experimental and modeling studies on foam flow in porous media particularly during the last decade, to stress the new achievements and highlight the areas that are less understood. X-ray computed tomography (CT) is a useful tool to study in-situ foam behaviors in porous media and new findings were obtained through this technology. The population-balance model was improved in different forms by researchers.

scholarly journals Investigation of Forced Convection Enhancement and Entropy Generation of Nanofluid Flow through a Corrugated Minichannel Filled with a Porous Media

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 1008
Author(s):  
Ehsan Aminian ◽  
Hesam Moghadasi ◽  
Hamid Saffari ◽  
Amir Mirza Gheitaghy
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Numerical Procedure ◽  
Numerical Data ◽  
Flow In Porous Media ◽  
Geometrical Parameters ◽  
Nanofluid Flow ◽  
Flow Through

Corrugating channel wall is considered to be an efficient procedure for achieving improved heat transfer. Further enhancement can be obtained through the utilization of nanofluids and porous media with high thermal conductivity. This paper presents the effect of geometrical parameters for the determination of an appropriate configuration. Furthermore, the optimization of forced convective heat transfer and fluid/nanofluid flow through a sinusoidal wavy-channel inside a porous medium is performed through the optimization of entropy generation. The fluid flow in porous media is considered to be laminar and Darcy–Brinkman–Forchheimer model has been utilized. The obtained results were compared with the corresponding numerical data in order to ensure the accuracy and reliability of the numerical procedure. As a result, increasing the Darcy number leads to the increased portion of thermal entropy generation as well as the decreased portion of frictional entropy generation in all configurations. Moreover, configuration with wavelength of 10 mm, amplitude of 0.5 mm and phase shift of 60° was selected as an optimum geometry for further investigations on the addition of nanoparticles. Additionally, increasing trend of average Nusselt number and friction factor, besides the decreasing trend of performance evaluation criteria (PEC) index, were inferred by increasing the volume fraction of the nanofluid (Al2O3 and CuO).

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