Multiple Solutions for Buoyancy-Induced Flow in Saturated Porous Media for Large Peclet Numbers

1986 ◽  
Vol 108 (4) ◽  
pp. 866-871 ◽  
Author(s):  
Rafiqul M. Islam ◽  
K. Nandakumar
Keyword(s):  
Porous Media ◽  
Flow Parameter ◽  
Axial Flow ◽  
Internal Heat ◽  
Saturated Porous Media ◽  
Vortex Pattern ◽  
Induced Flow ◽  
Model Equations ◽  
Buoyancy Induced Flow ◽  
Two Parameter

The problem of buoyancy-induced secondary flow in fluid-saturated porous media is examined using a numerical model. The natural convection is coupled either with a forced axial flow or uniform internal heat generation. In both cases the model equations are shown to exhibit dual solutions over certain ranges of flow parameter. In the two-parameter space of aspect ratio and Grashof number, the flow transition between the two-vortex and four-vortex pattern can be explained in terms of a tilted cusp.

Buoyancy-Induced Flow in Open Rotating Cavities

2007 ◽  
Vol 129 (4) ◽  
pp. 893-900 ◽  
Author(s):  
J. Michael Owen ◽  
Hans Abrahamsson ◽  
Klas Lindblad
Keyword(s):  
Tangential Velocity ◽  
Axial Flow ◽  
Quantitative Agreement ◽  
Turbine Engines ◽  
The Third ◽  
Commercial Code ◽  
Heated Disk ◽  
Induced Flow ◽  
Cooling Air ◽  
Buoyancy Induced Flow

Buoyancy-induced flow can occur in the cavity between the co-rotating compressor disks in gas-turbine engines, where the Rayleigh numbers can be in excess of 1012. In most cases the cavity is open at the center, and an axial throughflow of cooling air can interact with the buoyancy-induced flow between the disks. Such flows can be modeled, computationally and experimentally, by a simple rotating cavity with an axial flow of air. This paper describes work conducted as part of ICAS-GT, a major European research project. Experimental measurements of velocity, temperature, and heat transfer were obtained on a purpose-built experimental rig, and these results have been reported in an earlier paper. In addition, 3D unsteady CFD computations were carried out using a commercial code (Fluent) and a RNG k‐ε turbulence model. The computed velocity vectors and contours of temperature reveal a flow structure in which, as seen by previous experimenters, “radial arms” transport cold air from the center to the periphery of the cavity, and regions of cyclonic and anticyclonic circulation are formed on either side of each arm. The computed radial distribution of the tangential velocity agrees reasonably well with the measurements in two of the three cases considered here. In the third case, the computations significantly overpredict the measurements; the reason for this is not understood. The computed and measured values of Nu for the heated disk show qualitatively similar radial distributions, with high values near the center and the periphery. In two of the cases, the quantitative agreement is reasonably good; in the third case, the computations significantly underpredict the measured values.

Buoyancy-Induced Flow in Open Rotating Cavities

2006 ◽  
Author(s):  
J. Michael Owen ◽  
Hans Abrahamsson ◽  
Klas Lindblad
Keyword(s):  
Tangential Velocity ◽  
Axial Flow ◽  
Quantitative Agreement ◽  
Turbine Engines ◽  
The Third ◽  
Commercial Code ◽  
Heated Disc ◽  
Induced Flow ◽  
Cooling Air ◽  
Buoyancy Induced Flow

Buoyancy-induced flow can occur in the cavity between the co-rotating compressor discs in gas-turbine engines, where the Rayleigh numbers can be in excess of 1012. In most cases the cavity is open at the centre, and an axial throughflow of cooling air can interact with the buoyancy-induced flow between the discs. Such flows can be modeled, computationally and experimentally, by a simple rotating cavity with an axial flow of air. This paper describes work conducted as part of ICAS-GT, a major European research project. Experimental measurements of velocity, temperature and heat transfer were obtained on a purpose-built experimental rig, and these results have been reported in an earlier paper. In addition, 3D unsteady CFD computations were carried out using a commercial code (Fluent) and an RNG k-ε turbulence model. The computed velocity vectors and contours of temperature reveal a flow structure in which, as seen by previous experimenters, ‘radial arms’ transport cold air from the centre to the periphery of the cavity, and regions of cyclonic and anti-cyclonic circulation are formed on either side of each arm. The computed radial distribution of the tangential velocity agrees reasonably well with the measurements in two of the three cases considered here. In the third case, the computations significantly over-predict the measurements; the reason for this is not understood. The computed and measured values of Nu for the heated disc show qualitatively similar radial distributions, with high values near the centre and the periphery. In two of the cases, the quantitative agreement is reasonably good; in the third case, the computations significantly under-predict the measured values.

COUPLING FINITE ELEMENTS APPLIED TO HYDRAULIC ANALYSIS IN SATURATED POROUS MEDIA

2019 ◽  
Author(s):  
Murilo Camargo ◽  
Pedro Cleto ◽  
Eduardo Alexandre Rodrigues ◽  
Heber Agnelo Antonel Fabbri ◽  
Osvaldo Luís Manzoli
Keyword(s):  
Porous Media ◽  
Finite Elements ◽  
Saturated Porous Media ◽  
Hydraulic Analysis

scholarly journals Experimental study of the supercritical CO 2 diffusion coefficient in porous media under reservoir conditions

2019 ◽  
Vol 6 (6) ◽  
pp. 181902 ◽  
Author(s):  
Junchen Lv ◽  
Yuan Chi ◽  
Changzhong Zhao ◽  
Yi Zhang ◽  
Hailin Mu
Keyword(s):  
Porous Media ◽  
Diffusion Coefficient ◽  
Oil Recovery ◽  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Elevated Pressure ◽  
Experimental Results ◽  
Saturated Porous Media ◽  
Reservoir Conditions ◽  
The Impact

Reliable measurement of the CO 2 diffusion coefficient in consolidated oil-saturated porous media is critical for the design and performance of CO 2 -enhanced oil recovery (EOR) and carbon capture and storage (CCS) projects. A thorough experimental investigation of the supercritical CO 2 diffusion in n -decane-saturated Berea cores with permeabilities of 50 and 100 mD was conducted in this study at elevated pressure (10–25 MPa) and temperature (333.15–373.15 K), which simulated actual reservoir conditions. The supercritical CO 2 diffusion coefficients in the Berea cores were calculated by a model appropriate for diffusion in porous media based on Fick's Law. The results show that the supercritical CO 2 diffusion coefficient increases as the pressure, temperature and permeability increase. The supercritical CO 2 diffusion coefficient first increases slowly at 10 MPa and then grows significantly with increasing pressure. The impact of the pressure decreases at elevated temperature. The effect of permeability remains steady despite the temperature change during the experiments. The effect of gas state and porous media on the supercritical CO 2 diffusion coefficient was further discussed by comparing the results of this study with previous study. Based on the experimental results, an empirical correlation for supercritical CO 2 diffusion coefficient in n -decane-saturated porous media was developed. The experimental results contribute to the study of supercritical CO 2 diffusion in compact porous media.

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