High Permeability Porous Media Research Articles

Transient behavior of fluid flow and heat transfer in vertical channels partially filled with porous medium: Effects of inertial term and viscous dissipation

In this article, transient hydrodynamic and heat-transfer behavior of Newtonian fluid flow in vertical parallel-plate channels partially filled with a porous medium has been investigated numerically. In this regard, the influences of macroscopic local inertial term and the viscous heating due to the viscous dissipation were taken into account in the momentum equations of porous region and the thermal energy equations, respectively. Moreover, Forchheimer–Brinkman extended Darcy model was used to model fluid flow in the porous region. In addition, an analytical solution was obtained in the case of negligible Brinkman and Forchheimer number values at the steady-state conditions. The predicted results were compared with those predicted by a two-parameter perturbation technique developed by the present authors at the steady-state conditions and good agreement was obtained. The predicted results clearly indicate that neglecting the inertial effect in high permeability porous media or high velocity flows can alter substantially the flow and heat transfer characteristics.

Study on Properties of Pectinate Hydrophobically Associating Polyacrylamide Solutions

In this article, the viscosifying abilities, rheological properties, flow characteristics of pectinate hydrophobically associating polymer (PHAP) solutions with different hydrophobe content were studied using technical methods of viscosity measurement, rheological and core flow experiments. Researches on viscosifying of different PHAPs at 20°C and 65°C in distilled water and saline indicate that, with the raise of hydrophobe content, viscosity of polymer solutions increases first and then decreases, which means that there should be a critical hydrophobe content( CHC). Below CHC, the anti-shear ability of polymer solutions enhances as hydrophobe content rises; while the shear resistance would fall down when and after the content reaches CHC. In high permeability porous media, all polymer solutions take on greater injectivity, and RFF can all be higher than 5, yet with the increasing of hydrophobe content, RF goes up first and then declines. It could be an effective way to enhance mobility control ability, improve polymer flooding effect in high permeability reservoirs and design polymer molecular structure more reasonably, using the pectinate structure and hydrophobic association interaction between polymer moleculars.

2D-cell experiment on methyl tert-butyl ether transport in saturated zone of groundwater

As an additive of gasoline, methyl tert-butyl ether (MTBE) has a higher solubility in water, which is about 20 times as high as that of benzene. This characteristic results in MTBE dissolving out of the gasoline into the soil and groundwater. Due to relative unique physicochemical behavior of MTBE it would be an ideal candidate for use in environmental forensic investigations. In order to study the transport and distribution of MTBE in saturated zone of ground water, a two-dimensional experimental cell was setup to simulate the real environment of the groundwater flow. The effects of soil and groundwater flow velocity on the MTBE transport were investigated. The results show that the mobile distance of MTBE in vertical direction was smaller than that in horizontal direction paralleling with the groundwater flow. Because the main dynamics of groundwater flow direction was convection and dispersion, the movement of MTBE is also diffusion in the vertical direction. In addition, the transport of MTBE was more quick in high permeability porous media, and the increase of groundwater flow velocity can accelerate the MTBE plume development, but the irregularity and randomness of the plume are enhanced synchronously. These research results can give some helps for the investigation of MTBE movement in the groundwater, also can make some references for other petroleum contamination behavior.

Forced Convection of a Power-Law Fluid in a Porous Channel—Integral Solutions

The integral method based on the boundary layer analysis is used to conduct a theoretical study of the primary hydrodynamic and heat transfer mechanisms for forced convection of a power-law fluid in a porous channel for both cases of uniform heat flux (UHF) and uniform wall temperature (UWT) boundary conditions. The flow in the porous medium is modeled using the modified Brinkman—Forchheimer-extended Darcy model for power-law fluids. The results indicate that for a high-permeability porous medium, the thickness of the momentum boundary layer depends on the Darcy number, inertia parameter, and power law index, but for a low-permeability porous medium it depends only on the Darcy number. Consequently in the non-Darcy regime, the effects of power law index on hydrodynamic and heat transfer behaviors in the porous channel are significant, whereas in the Darcy regime, the effects of Darcy number are predominant. Also the hydrodynamic behavior of shear thickening fluids (n > 1.0) is more sensitive to the Darcy number whereas the behavior of shear thinning fluids (n < 1.0) is more sensitive to the inertia parameter in the non-Darcy regime. Based on the fully developed Nusselt number solutions, the valid region for the applicability of the present integral method is illustrated graphically. The valid region of the integral solutions covers the Darcy regime for any value of the power law index within the range considered, while in the non-Darcy regime, the valid region for a shear thinning fluid becomes smaller than that for a shear thickening fluid as the inertia parameter decreases.

Forchheimer and Brinkman extended Darcy flow model on natural convection in a vertical cylindrical porous annulus

In the present numerical work, the Forchheimer and Brinkman extended Darcy flow model is used for studying the natural convection heat transfer in a vertical cylindrical porous annulus. Forchheimer inertial and Brinkman viscous terms have been characterized by two non-dimensional numbers. The present description renders the formulation suitable for vertical annuli as well as for rectangular cavity. Numerical results obtained by SAR scheme indicate, that Brinkman viscous terms lead to a higher decrease in the average Nusselt number compared to the Forchheimer inertial terms. Numerical results obtained with the present non-Darcy flow model are in good agreement with the available experimental results of a high permeability porous medium for which results obtained with the Darcy flow model show considerable deviation.