Mass transfer in an electrochemical reactor with two interacting jets
Abstract
An electrochemical reactor operated with two identical solution streams injected in opposite directions on the same axis, and leaving it at a normal direction was studied by measuring local and global mass transfer coefficients and visualization of solution flow patterns. This flow configuration was compared to a case where a single stream enters the reactor and leaves it on the same axis. It was found that only the data obtained for the single stream mode can be correlated by the Chilton-Colburn relation, indicating a near laminar boundary layer flow. Global mass transfer coefficients for the single stream mode were found to be slightly higher than those for the interacting jets mode. However, when comparing the two modes by taking into account the dimensionless ratio of the mass transfer coefficient (Sh) to the energy consumption (Eu), it was found that the interacting jets (IJ) mode exhibits a better performance as compared to the single stream mode. The superiority of the IJ mode increases with increasing Reynold's number (Re).
Keywords
Boundary Layer Mass Transfer Flow Pattern Normal Direction Mass Transfer CoefficientNomenclature
- A, B
adjustable parameters
- b
half width of channel
- C
electrolyte ion concentration
- d
inlet pipe diameter
- d′
microelectrode diameter
- D
diffusion coefficient
- \(\overline D _{max} \)
maximum value of mean deviation
- E
pumping energy
- Eu
Euler number
- F
Faraday number
- i
current to a single microelectrode on an active wall
- i′
current to a single microelectrode in an inert wall
- I
global diffusion current
- k
mass transfer coefficient to a single microelectrode in an active wall
- k′
mass transfer coefficient to a single microelectrode in an inert wall
- K
global mass transfer coefficient
- Q
volumetric flow rate
- QT
total volumetric flow rate
- R
radius of the electrochemical reactor
- Re
Reynolds number
- s
surface area of a microelectrode
- S
surface area of the working electrode
- Sc
Schmidt number
- Sh
Sherwood number
- Vx
axial flow velocity alongx-axis
- V∞
flow velocity at large distance from the leading edge
- V
mean flow velocity
- x
axis tangential to the surface
- y
axis normal to the surface
- z
number of electrons transferred in the reaction (z=1 in the present case)
Greek letters
- μ
viscosity
- ρ
specific gravity
- ν
kinematic viscosity (μ/ρ)
- ΔP
pressure drop across the reactor
- ΔV
voltage drop across the reactor
Abbreviations
- ST
single stream
- IJ
interacting jets
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