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.
Similar content being viewed by others
Abbreviations
- A e :
-
effective area of electrode, m2
- C L :
-
concentration, mol/m3
- C xx :
-
auto-correlation function of signal x
- d ip :
-
distance between two probes, m
- d′m :
-
average structure dimension, m
- d′M :
-
maximum structure size, m
- D :
-
diffusion coefficient, m2/s
- d e :
-
electrode diameter, m
- f :
-
frequency, s−1
- F :
-
Faraday constant, 96,500 C/equi
- F D(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
- P xx :
-
Power spectral density of signal x
- Re p :
-
\( = \frac{{\rho _{{\text{L}}} u_{0} d_{{\text{p}}} }} {\mu } \), particle Reynolds number
- S :
-
velocity gradient, s−1
- t :
-
time, s
- T c :
-
integral coherence time, s
- u L :
-
liquid phase velocity, m/s
- u′L :
-
fluctuation of liquid phase velocity, m/s
- α L :
-
fluid volume fraction
- ε :
-
porosity
- μ :
-
liquid kinematic viscosity, Pa s
- ν e :
-
number of electrons involved in the electrochemical reaction
- ρ L :
-
liquid phase specific gravity, kg/m3
- ρ 0 :
-
local liquid phase specific gravity, kg/m3
- θ :
-
time lag (in correlation functions), s
- θ c :
-
coherence time, s
- τ :
-
tortuosity
- ω :
-
dimensionless frequency
References
Antohe BV, Lage JL (1997) A general two-equation macroscopic turbulence model for incompressible flow in porous media. Int J Heat Mass Transfer 40:3013–3024
Bard AJ, Faulkner LR (1980) Electrochemical methods. Wiley, New York
Benenati RF, Brosilow CB (1962) Void fraction distribution in beds of spheres. AIChE J 8:359–361
Deslouis C, Gil O, Tribollet B (1993) Frequency response of small electrodes to hydrodynamic or to potential perturbations. Electrochem Acta 38:1847–1856
Jolls KR, Hanratty TJ (1966) Transition to turbulence for flow through a dumped bed of spheres. Chem Eng Sci 21:1185–1190
Kashiwa BA, Rauenzahn RM (1994) A multimaterial formalism. In: Numerical methods in multiphase flows. ASME, New York, pp 149–157
Latifi MA, Midoux N, Storck A, Gence JN (1989) The use of micro-electrodes in the study of the flow regimes in a packed bed reactor with single phase liquid flow. Chem Eng Sci 44:2501–2508
Naderifar A (1995) Étude expérimentale locale et globale du transfert de matière liquide/solide à la paroi d’un réacteur à lit fixe. PhD thesis, Institut National Polytechnique de Lorraine, France
Nakoryakov VE, Kashinsky ON, Kozmenko BK (1983) Electrochemical method for measuring turbulent characteristics of gas–liquid flows. In: Measuring techniques in gas–liquid two-phase flows, IUTAM Symposium, Nancy, France, pp 695–721
Reiss LR (1962) Investigation of turbulence near a pipe wall using a diffusion controlled electrolyte reaction on a circular electrode. PhD thesis, University of Illinois, Urbana, USA
Reiss LR, Hanratty TJ (1963) An experimental study of the unsteady nature of viscous sublayer. AIChE J 9:154–160
Rode S (1992) Analyse spatio-temporelle des phénomènes hydrodynamiques et de transfert de matière au sein d’un réacteur à lit fixe opérant en écoulement monophasique de liquide ou en co-courant vers le bas de gaz et de liquide; mise en oeuvre de la technique des microsondes électrochimiques. PhD thesis, Institut National Polytechnique de Lorraine, France
Seguin D, Montillet A, Comiti J (1998a) Experimental characterisation of flow regimes in various porous media—I: Limit of laminar flow regime. Chem Eng Sci 53:3751–3761
Seguin D, Montillet A, Comiti J, Huet F (1998b) Experimental characterisation of flow regimes in various porous media—II: Transition to turbulent regime. Chem Eng Sci 53:3897–3909
Storck A, Coeuret F (1984) Éléments de génie électrochimique. Lavoisier, Paris, France
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Lesage, F., Midoux, N. & Latifi, M.A. New local measurements of hydrodynamics in porous media. Exp Fluids 37, 257–262 (2004). https://doi.org/10.1007/s00348-004-0811-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00348-004-0811-5