Mass and heat transfer at a corrugated wall of a square stirred tank reactor and possible applications

ABSTRACT

The electrochemical technique was used to investigate the effect of surface corrugations on the rate of mass and heat transfer (by analogy) in a stirred tank reactor. Impeller rotational speed, impeller shape, corrugation peak to valley height, and corrugation orientation (horizontal or vertical) were among the variables investigated. Depending on the operating conditions, surface corrugation increased the volumetric mass transfer coefficient by a factor ranging from 1.16 to 3.7. Mass transfer data were correlated with dimensionless correlations of an average deviation of ±4.2 and ±5.49 for radial and axial flow turbines, respectively. The significance of the dimensionless equations in determining the rate of heat transfer from the corrugated wall to a cooling jacket was emphasized.

KEYWORDS:

• Biochemical Reactors
• Catalytic reactors
• Corrugated surfaces
• Electrochemical reactors
• Mass transfer

List of symbols

A	=	Projected area of the corrugated wall (m2)
$\bar{\mathrm{A}}$	=	Actual area of the corrugated wall (m2)
C	=	Ferricyanide concentration (mole/m3)
Cp	=	Heat capacity (J/kg.${ }^{\circ }\mathrm{C}$)
D	=	Diffusion coefficient (m2/s)
de	=	Tank equivalent diameter (m)
di	=	Impeller diameter (m)
F	=	faraday’s constant (96500 Coulombs)
h	=	Inner side heat transfer coefficient (W/m2.${ }^{\circ }\mathrm{C}$)
I	=	Limiting current (Ampere)
k	=	Mass transfer coefficient (m/s)
L	=	Cathode (wall) height (m)
n	=	Impeller rotational speed (r.p.m)
p	=	Corrugation peak to valley height (m)
$\bar{\mathrm{P}}$	=	Mechanical power consumption (W)
Z	=	Number of electrons involved
Greek letters	=
${ }^{\circ }\mathit{C}$	=	Specific power consumption (W/kg)
$\mathit{\lambda }$	=	Thermal conductivity (W/m.${ }^{\circ }\mathrm{C}$)
$\mathit{\mu }$	=	Solution viscosity (kg/m.s)
$\mathit{\nu }$	=	Kinematic viscosity (m2/s)
$\mathit{\rho }$	=	Solution density (kg/m3)
Dimesnionless groups	=
Np	=	Power number ($\bar{\mathrm{P}}/\mathit{\rho }{\mathrm{n}}^3{{\mathrm{d}}_{\mathrm{i}}}^5$)
Nu	=	Nusselt number ($\mathrm{hL}/\mathit{\lambda }$)
Pr	=	Prandtl number ($\mathit{\mu }{\mathrm{C}}_{\mathrm{p}}/\mathit{\lambda }$)
Re	=	Reynolds number ($\mathit{\rho }\mathrm{n}{{\mathrm{d}}_{\mathrm{i}}}^2/\mathit{\mu }$)
Sc	=	Schmidt number ($\mathit{\mu }/\mathit{\rho }\mathrm{D}$)
Sh	=	Sherwood number ($\mathrm{kL}/\mathrm{D}$)

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

The work was supported by the This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors [N/A].