Interception efficiency in two - dimensional flow past confined porous cylinders
نویسندگان
چکیده
The flow interception efficiency, which provides a measure of the fraction of streamlines that intercept a porous collector, is an important parameter in applications such as particle capture, filtration, and sedimentation. In this work, flow permeation through a porous circular cylinder located symmetrically between two impermeable parallel plates is investigated numerically under different flow and geometrical conditions. A flow interception efficiency is defined and calculated based on the flow permeation rate for a wide range of system parameters. The dependencies on all physical variables can be captured in three dimensionless numbers: the Reynolds number, the Darcy number (ratio of permeability to the square of cylinder diameter), and the plate separation relative to the cylinder size. The flow interception efficiency is very low in the limit of unbounded cylinders but significantly increases by restricting the flow domain. The fluid permeation rate through the porous cylinder varies nonlinearly with the relative plate/cylinder spacing ratio, especially when the gap between the cylinder and the confining plates is small compared to the cylinder size. In general, the effects of the Reynolds number, the Darcy number, and confinement on the flow interception efficiency are coupled; however, for most practical cases it is possible to factorize these effects. For practical ranges of the Darcy number (Da < 10, which means that the pore size is at least one order of magnitude smaller than the porous cylinder diameter), the interception efficiency varies linearly with Da, is independent of the Reynolds number at low Reynolds numbers (ReD < 10), and varies linearly with Reynolds number at higher flow rates. In addition to numerical solutions, theoretical expressions are developed for the flow interception efficiency in two limiting cases of confined and unbounded flow, based on modeling the system as a network of hydrodynamic resistances, which agree well with the numerical results. Furthermore, an expression for 1 Corresponding author; email: [email protected]
منابع مشابه
A Computational Approach to the Flow of Walter’s Liquid B′ through Annulus of Coaxial Porous Circular Cylinders for High Suction Parameter (RESEARCH NOTE)
The present investigation studies the behavior of steady flow of visco-elastic liquid between two porous coaxial circular cylinders, where both the cylinders are rotating with different uniform angular velocities about the common axis. In addition, the inner cylinder has uniform velocity along the axis and the visco-elastic fluid, which is a Walters liquid B′, is allowed to flow in the annulus....
متن کاملPressure Calculation in the Flow Between Two Rotating Eccentric Cylinders at High Renolds Numbers
This paper reports the result of an analytical investigation of a steady, incompressible and viscous flow between two eccentric, rotating cylinders at high Reynolds number. A one dimensional case is far from reality because the gap between the cylinders is very small. Further, when their axes are displaced by a small distance, usually caused by bearing loads, two dimensional effects become obvi...
متن کاملNatural convection from horizontal noncircular annulus partially filled with porous sleeve
In this paper natural convection heat transfer within a two-dimensional, horizontal, concentric cam shape cylinders that is partially filled with a fluid saturated porous medium has been investigated. both cylinder are kept at constant and uniform temperatures with the outer cylinder being subjected relatively lower than the inner one. In addition the forchheimer and brinkman effect are taken i...
متن کاملLBM mesoscale modelling of porous media
Permeability is one of the most important bulk properties for the characterization of fluid flow in porous media. However, despite all the considerable body of research work over the past years using experimental, analytical, and numerical approaches, its determination is still a challenge. The methodologies, which have been used to measure, calculate and predict the permeability of different t...
متن کاملDispersion and Deposition of Micro Particles over Two Square Obstacles in a Channel via Hybrid Lattice Boltzmann Method and Discrete Phase model
Dispersion and deposition of aerosol particles over two square cylinders confined in a channel in laminar unsteady vortical flow were investigated numerically. Lattice Boltzmann method was used to calculate fluid characteristics and modify Euler method was employed as Lagrangian particle tracing procedure to obtain particle trajectories. Drag, Saffman lift, gravity, buoyancy and Brownian motion...
متن کامل