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Experiments in Fluids

, Volume 37, Issue 2, pp 257–262 | Cite as

New local measurements of hydrodynamics in porous media

  • F. Lesage
  • N. Midoux
  • M. A. Latifi
Original

Abstract

In this paper, a measurement system is used to carry out local hydrodynamic measurements at the pore scale of a fixed-bed reactor. It consists of four microelectrodes placed on the inner wall of four spheres mounted in tetrahedral form, thus constituting a pore of the fixed bed. Three flow regimes (laminar, inertial and turbulent-like) are identified by the analysis of the signal fluctuations (velocity gradient). The flow structures are characterised by means of the correlation (auto- and cross-) function analysis, and a closure equation required in modelling and simulation is suggested.

Keywords

Porous Medium Reynolds Stress Coherence Time Fluctuation Rate Reynolds Stress Tensor 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols

Ae

effective area of electrode, m2

CL

concentration, mol/m3

Cxx

auto-correlation function of signal x

dip

distance between two probes, m

dm

average structure dimension, m

dM

maximum structure size, m

D

diffusion coefficient, m2/s

de

electrode diameter, m

f

frequency, s−1

F

Faraday constant, 96,500 C/equi

FD(L–S)

liquid–solid momentum exchange term, kg/m2/s2

g

gravity, 9.81 m/s2

H

transfer function

I

limiting current, A

L

liquid flow rate, kg/m2/s

P

static pressure, Pa

Pxx

Power spectral density of signal x

Rep

\( = \frac{{\rho _{{\text{L}}} u_{0} d_{{\text{p}}} }} {\mu } \), particle Reynolds number

S

velocity gradient, s−1

t

time, s

Tc

integral coherence time, s

uL

liquid phase velocity, m/s

uL

fluctuation of liquid phase velocity, m/s

Greek symbols

αL

fluid volume fraction

ε

porosity

μ

liquid kinematic viscosity, Pa s

νe

number of electrons involved in the electrochemical reaction

ρL

liquid phase specific gravity, kg/m3

ρ0

local liquid phase specific gravity, kg/m3

θ

time lag (in correlation functions), s

θc

coherence time, s

τ

tortuosity

ω

dimensionless frequency

References

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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Laboratoire des Sciences du Génie ChimiqueCNRS-ENSICNancyFrance

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