Simultaneous mass and heat transfer to a plate electrode in the region of free convection with antiparallel fluxes of mass and heat

1983 ◽  
Vol 48 (8) ◽  
pp. 2213-2231 ◽  
Author(s):  
Petr Novák ◽  
Ivo Roušar
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Vertical Plate ◽  
Limiting Current ◽  
Navier Stokes ◽  
Plate Electrode ◽  
Criterion Equation ◽  
Transfer Equations ◽  
Current Densities ◽  
Mass And Heat Transfer

Simultaneous transfer of heat and ions to a vertical plate electrode in the region of free convection was treated mathematically by solving the Navier-Stokes, convective diffusion, and convective heat transfer equations. The direction of flow due to heat flux was considered opposite to that due to flux of ions. A criterion equation was proposed for the calculation of the Sherwood criterion with an error smaller than 2%. This was verified experimentally by measuring the limiting current densities for electrolytes containing K4Fe(CN)6 and K3Fe(CN)6 with KOH as base electrolyte.

scholarly journals Computational Analysis of Natural Convection Heat Transfer on a Vertical Plate with Discrete Heat Sources

2020 ◽  
Vol 9 (3) ◽  
pp. 3736-3742
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Vertical Plate ◽  
Stokes Equations ◽  
Convection Heat Transfer ◽  
Navier Stokes ◽  
Heat Sources ◽  
Convection Heat ◽  
Grashof Number ◽  
Discrete Heat Sources

In the present study, buoyancy driven free convection flow along the vertical plate with discrete heat sources is analyzed. To illustrate free convection heat transfer along a vertical plate with finite discrete heat sources a 2-D steady-state model is considered. The thermos-physical properties of fluid are assumed constant except for the buoyancy terms, which are computed using the Boussinesq approximation of Navier-stokes equation. The two-dimensional Navier-stokes equations are solved using SIMPLER algorithm. The dimensionless equations are descretised and solved by using central difference finite difference approach. The development of the air flow caused by buoyancy induced free convective heat transfer has been studied through the progression of velocity and temperature fields. The results are obtained for various Grashof numbers Gr=103 , 104 and 5x 104 , and the influence of Grashof number on flow field has been studied. Average Nusselt number at the plate is also obtained. The effect of variation of Prandtl number at a given Grashof number is also studied.

Simultaneous flow of ions and heat to a plate electrode in the region of natural convection

1979 ◽  
Vol 44 (6) ◽  
pp. 1857-1868 ◽  
Author(s):  
Petr Novák ◽  
Ivo Roušar
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Natural Convection ◽  
Convective Diffusion ◽  
Navier Stokes ◽  
Exponential Polynomials ◽  
Plate Electrode ◽  
Transfer Equations ◽  
Boundary Layer Region ◽  
Layer Region

The Sherwood criterion was calculated for a flow of ions to the surface of a plate electrode during natural convection by solving the Navier-Stokes, convective diffusion, and convective heat transfer equations. The solution for the boundary layer region was performed by the collocation method using orthogonal exponential polynomials. Values of the Sh criterion were obtained for Sc ##m <500; 2 000>, Pr ##m <5; 20>, and GrT/GrM ##m <0.2; 8.0>. A comparison with literature data revealed the best agreement with average errors of +2.0 and -1.4%. Another equation with an error of only +0.5% is proposed.

Laminar and Turbulent Free Convection From Elliptic Cylinders, With a Vertical Plate and Horizontal Circular Cylinder as Special Cases

1976 ◽  
Vol 98 (1) ◽  
pp. 72-80 ◽  
Author(s):  
G. D. Raithby ◽  
K. G. T. Hollands
Keyword(s):  
Heat Transfer ◽  
Circular Cylinder ◽  
Free Convection ◽  
Vertical Plate ◽  
Constant Heat Flux ◽  
Special Cases ◽  
Flux Boundary Conditions ◽  
Large Eccentricity ◽  
Rayleigh Numbers ◽  
Horizontal Circular Cylinder

Heat transfer by free convection from thin elliptic cylinders is predicted, accounting for both the effect of thick boundary layers at low Rayleigh numbers and the influence of turbulence at higher Rayleigh numbers. Isothermal and constant heat flux boundary conditions are treated. The results are compared with experimental data, which are available for the limiting cases of large eccentricity (vertical plate) and small eccentricity (horizontal circular cylinder); the agreement is excellent. Accurate correlation equations, from which the average heat transfer can be calculated, are given.

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