Topic
Countercurrent exchange
About: Countercurrent exchange is a research topic. Over the lifetime, 2255 publications have been published within this topic receiving 28687 citations. The topic is also known as: Countercurrent exchange.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: In this article, a theoretical dispersed plug flow model that includes a mass-transfer resistance represented by a linear driving force approximation is developed for unsteady-state continuous countercurrent adsorption systems having nonlinear equilibrium isotherms.
9 citations
••
TL;DR: In this article, a self-consistent system of macroscopic equations, including Leverett's equation for capillary pressure, is presented for determining experimentally relative permeability and capillary pressures as a function of saturation.
Abstract: When determining experimentally relative permeability and capillary pressure as a function of saturation, a self-consistent system of macroscopic equations, that includes Leverett's equation for capillary pressure, is required. In this technical note, such a system of equations, together with the conditions under which the equations apply, is formulated. With the aid of this system of equations, it is shown that, at the inlet boundary of a vertically oriented porous medium, static conditions pertain, and that potentials, because of the definition of potential, are equal in magnitude to pressures. Consequently, Leverett's equation is valid at the inlet boundary of the porous medium, provided cocurrent flow, or gravity-driven, countercurrent flow is taking place, and provided the porous medium is homogeneous. Moreover, it is demonstrated that Leverett's equation is valid for flow along the length of a vertically oriented porous medium, provided cocurrent flow, or gravity-driven, countercurrent flow is taking place, and provided the porous medium is homogeneous and there are no hydrodynamic effects. However, Leverett's equation is invalid for horizontal, steady-state, forced, countercurrent flow. When such flow is taking place, it is the sum of the pressures, and not the difference in pressures, which is related to capillary pressure.
9 citations
••
TL;DR: In this paper, the authors explore the various experimental parameters of IMA to determine which of these can be used to control the column spacing, including the field frequency, strength, and phase relation between the two field components, the liquid viscosity, and particle volume fraction.
Abstract: Isothermal magnetic advection (IMA) is a recently discovered method of inducing highly organized, non-contact flow lattices in suspensions of magnetic particles, using only uniform ac magnetic fields of modest strength. The initiation of these vigorous flows requires neither a thermal gradient nor a gravitational field, and so can be used to transfer heat and mass in circumstances where natural convection does not occur. These advection lattices are comprised of a square lattice of antiparallel flow columns. If the column spacing is sufficiently large compared to the column length and the flow rate within the columns is sufficiently large, then one would expect efficient transfer of both heat and mass. Otherwise, the flow lattice could act as a countercurrent heat exchanger and only mass will be efficiently transferred. Although this latter case might be useful for feeding a reaction front without extracting heat, it is likely that most interest will be focused on using IMA for heat transfer. In this paper, we explore the various experimental parameters of IMA to determine which of these can be used to control the column spacing. These parameters include the field frequency, strength, and phase relation between the two field components, the liquid viscosity, and particle volume fraction. We find that the column spacing can easily be tuned over a wide range to enable the careful control of heat and mass transfer.
9 citations
••
TL;DR: In this article, a high Reynolds number turbulence model is proposed for the countercurrent flow of air and water in a vertical circular pipe, where hot water is introduced through a porous section at the upper end of a test section and flows downward as a thin liquid film on the pipe wall.
9 citations