Effect of thermal conductivity on the gravitational instability of a magnetized rotating plasma through a porous medium in the presence of suspended particles

1988 ◽  
Vol 145 (2) ◽  
pp. 223-240 ◽  
Author(s):  
R. K. Chhajlani ◽  
M. K. Vyas
Keyword(s):  
Thermal Conductivity ◽  
Porous Medium ◽  
Gravitational Instability ◽  
Suspended Particles

Two-Phase Multicomponent Diffusion and Convection for Reservoir Initialization

2006 ◽  
Vol 9 (05) ◽  
pp. 530-542 ◽  
Author(s):  
Hadi Nasrabadi ◽  
Kassem Ghorayeb ◽  
Abbas Firoozabadi
Keyword(s):  
Thermal Conductivity ◽  
Porous Medium ◽  
Natural Convection ◽  
Temperature Gradient ◽  
Thermal Diffusion ◽  
Multicomponent Diffusion ◽  
Compositional Variation ◽  
Horizontal Temperature Gradient ◽  
Two Phase ◽  
Thermogravitational Column

Summary We present formulation and numerical solution of two-phase multicomponent diffusion and natural convection in porous media. Thermal diffusion, pressure diffusion, and molecular diffusion are included in the diffusion expression from thermodynamics of irreversible processes. The formulation and the numerical solution are used to perform initialization in a 2D cross section. We use both homogeneous and layered media without and with anisotropy in our calculations. Numerical examples for a binary mixture of C1/C3 and a multicomponent reservoir fluid are presented. Results show a strong effect of natural convection in species distribution. Results also show that there are at least two main rotating cells at steady state: one in the gas cap, and one in the oil column. Introduction Proper initialization is an important aspect of reliable reservoir simulations. The use of the Gibbs segregation condition generally cannot provide reliable initialization in hydrocarbon reservoirs. This is caused, in part, by the effect of thermal diffusion (caused by the geothermal temperature gradient), which cannot be neglected in some cases; thermal diffusion might be the main phenomenon affecting compositional variation in hydrocarbon reservoirs, especially for near-critical gas/condensate reservoirs (Ghorayeb et al. 2003). Generally, temperature increases with increasing burial depth because heat flows from the Earth's interior toward the surface. The temperature profile, or geothermal gradient, is related to the thermal conductivity of a body of rock and the heat flux. Thermal conductivity is not necessarily uniform because it depends on the mineralogical composition of the rock, the porosity, and the presence of water or gas. Therefore, differences in thermal conductivity between adjacent lithologies can result in a horizontal temperature gradient. Horizontal temperature gradients in some offshore fields can be observed because of a constant water temperature (approximately 4°C) in different depths in the seabed floor. The horizontal temperature gradient causes natural convection that might have a significant effect on species distribution (Firoozabadi 1999). The combined effects of diffusion (pressure, thermal, and molecular) and natural convection on compositional variation in multicomponent mixtures in porous media have been investigated for single-phase systems (Riley and Firoozabadi 1998; Ghorayeb and Firoozabadi 2000a).The results from these references show the importance of natural convection, which, in some cases, overrides diffusion and results in a uniform composition. Natural convection also can result in increased horizontal compositional variation, an effect similar to that in a thermogravitational column (Ghorayeb and Firoozabadi 2001; Nasrabadi et al. 2006). The combined effect of convection and diffusion on species separation has been the subject of many experimental studies. Separation in a thermogravitational column with both effects has been measured widely (Schott 1973; Costeseque 1982; El Mataaoui 1986). The thermogravitational column consists of two isothermal vertical plates with different temperatures separated by a narrow space. The space can be either without a porous medium or filled with a porous medium. The thermal diffusion, in a binary mixture, causes one component to segregate to the hot plate and the other to the cold plate. Because of the density gradient caused by temperature and concentration gradients, convection flow occurs and creates a concentration difference between the top and bottom of the column. Analytical and numerical models have been presented to analyze the experimental results (Lorenz and Emery 1959; Jamet et al. 1992; Nasrabadi et al. 2006). The experimental and theoretical studies show that the composition difference between the top and bottom of the column increases with permeability until an optimum permeability is reached. Then, the composition difference declines as permeability increases. The process in a thermogravitational column shows the significance of the convection from a horizontal temperature gradient.

Experimental investigation of suspended particles transport in porous medium under variable temperatures

2019 ◽  
Vol 33 (7) ◽  
pp. 1117-1126 ◽  
Author(s):  
Xianze Cui ◽  
Yong Fan ◽  
Hongxing Wang ◽  
Shibing Huang
Keyword(s):  
Experimental Investigation ◽  
Porous Medium ◽  
Suspended Particles

scholarly journals Thermosolutal Instability in Compressible Viscoelastic Dusty Fluid through Porous Medium

2013 ◽  
Vol 18 (1) ◽  
pp. 99-112 ◽  
Author(s):  
P. Kumar ◽  
H. Mohan
Keyword(s):  
Porous Medium ◽  
Viscoelastic Fluid ◽  
Normal Mode Analysis ◽  
Suspended Particles ◽  
Mode Analysis ◽  
Stationary Convection ◽  
Linearized Stability ◽  
Medium Permeability ◽  
The Stability ◽  
Solute Gradient

Thermosolutal instability in a compressible Walters B’ viscoelastic fluid with suspended particles through a porous medium is considered. Following the linearized stability theory and normal mode analysis, the dispersion relation is obtained. For stationary convection, the Walters B’ viscoelastic fluid behaves like a Newtonian fluid and it is found that suspended particles and medium permeability have a destabilizing effect whereas the stable solute gradient and compressibility have a stabilizing effect on the system. Graphs have been plotted by giving numerical values to the parameters to depict the stability characteristics. The stable solute gradient and viscoelasticity are found to introduce oscillatory modes in the system which are non-existent in their absence.

From micro/nano structured isotactic polypropylene to a multifunctional low-density nanoporous medium

RSC Advances ◽  
2016 ◽  
Vol 6 (109) ◽  
pp. 108056-108066 ◽  
Author(s):  
Mehdi Saniei ◽  
Minh-Phuong Tran ◽  
Seong-Soo Bae ◽  
Piyapong Boahom ◽  
Pengjian Gong ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Thermal Conductivity ◽  
Porous Medium ◽  
Supercritical Carbon Dioxide ◽  
Isotactic Polypropylene ◽  
Low Density ◽  
Low Thermal Conductivity ◽  
Supercritical Carbon

A homogeneous low-density nano-porous medium of isotactic polypropylene (iPP) with a low thermal conductivity was fabricated using supercritical carbon dioxide (scCO2).

USE OF NANOFLUIDS BASED ON CARBON NANOPARTICLES TO DISPLACE OIL FROM THE POROUS MEDIUM MODEL

2020 ◽  
Vol 6 (4) ◽  
pp. 141-157
Author(s):  
Yuri V. Pakharukov ◽  
Farid K. Shabiev ◽  
Ruslan F. Safargaliev ◽  
Boris S. Yezdin ◽  
Valery V. Kalyada
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Porous Medium ◽  
Synergistic Effect ◽  
Transition Region ◽  
Dimensional Structure ◽  
Hybrid Nanofluids ◽  
Scanning Electron

Graphene, due to its two-dimensional structure, has some unique properties. For example, the thermal conductivity and electrical conductivity of graphene are an order of magnitude higher than the thermal conductivity and electrical conductivity of copper. For this reason, graphene-based nanofluids are now used in many industries. Due to the effect of self-organization of graphene nanoparticles with hydrocarbon molecules, the use of graphene has become possible in the oil industry. Graphene-based nanofluids are used as a displacement fluid to increase the oil recovery coefficient. The displacing ability of graphene-based nanofluids is concentration dependent. An increase in the concentration of nanoparticles entails an increase in viscosity, which negatively affects the performance characteristics of the nanofluid. This problem is partially solved due to the synergistic effect, hybrid nanofluids consisting of nanoparticles of graphene and metals or carbides enhance the displacing ability. Using atomic force microscopy, scanning electron microscopy and molecular modelling methods, this work has studied the formation of supramolecular structures that form a transition region at the oil-nanofluid interface with low surface tension as a result of a synergistic effect in the interaction of graphene planar nanoparticles and silicon carbide nanoparticles covered with graphene layers (Core-shell). The model experiments on a Hele-Shaw cell have shown that in a porous medium, such hybrid nanofluids have a high displacement ability of residual oil. At the same time, the oil — nanofluid interface remains stable, without the formation of viscous fingers. During the study by scanning electron microscopy, a transition region was observed, in the structuring of which the nanoparticles were directly involved. The displacement efficiency of a hybrid nonofluid depends on the concentration of nanoparticles and their interaction.

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