Mass Transfer During Fluid Sphere Dissolution in an Alternating Electric Field

Volume 3 ◽  
2004 ◽  
Author(s):  
Tov Elperin ◽  
Andrew Fominykh ◽  
Zakhar Orenbakh
Keyword(s):  
Mass Transfer ◽  
Electric Field ◽  
Applied Electric Field ◽  
Fluid Motion ◽  
Analytical Form ◽  
Internal Resistance ◽  
Creeping Flow ◽  
Fluid Sphere ◽  
Droplet Deformation ◽  
Alternating Electric Field

In this study we considered mass transfer in a binary system comprising a stationary fluid dielectric sphere embedded into an immiscible dielectric liquid under the influence of an alternating electric field. Fluid sphere is assumed to be solvent-saturated so that an internal resistance to mass transfer can be neglected. Mass flux is directed from a fluid sphere to a host medium, and the applied electric field causes a creeping flow around the sphere. Droplet deformation under the influence of the electric field is neglected. The problem is solved in the approximations of a thin concentration boundary layer and finite dilution of a solute in the solvent. The thermodynamic parameters of a system are assumed constant. The nonlinear partial parabolic differential equation of convective diffusion is solved by means of a generalized similarity transformation, and the solution is obtained in a closed analytical form for all frequencies of the applied electric field. The rates of mass transfer are calculated for both directions of fluid motion — from the poles to equator and from the equator to the poles. Numerical calculations show essential (by a factor of 2–3) enhancement of the rate of mass transfer in water droplet–benzonitrile and droplet of carbontetrachloride–glycerol systems under the influence of electric field for a stagnant droplet. The asymptotics of the obtained solutions are discussed.

Numerical Analysis of Heat and Mass Transfer From Fluid Spheres in an Electric Field

1986 ◽  
Vol 108 (2) ◽  
pp. 337-342 ◽  
Author(s):  
L. Sharpe ◽  
F. A. Morrison
Keyword(s):  
Mass Transfer ◽  
Electric Field ◽  
Radial Flow ◽  
Numerical Solutions ◽  
Creeping Flow ◽  
Dimensionless Temperature ◽  
Flow Heat ◽  
Steady State Heat ◽  
Transmitting Boundary ◽  
Finite Difference Techniques

Steady-state heat or mass transfer to a drop in an electric field at low values of the Reynolds number is investigated. The energy equation is solved using finite difference techniques; upwind differencing is used in approximating the convective terms. Far from the sphere, a “transmitting” boundary condition is introduced; the dimensionless temperature is held at zero for inward radial flow and the dimensionless temperature gradient is held at zero for outward radial flow at a fixed distance from the sphere’s surface. Numerical solutions are obtained using an iterative method. Creeping flow heat transfer results are obtained for Peclet numbers up to 103.

Transient Heat Transfer in a Fluid Sphere Translating in an Electric Field

1990 ◽  
Vol 112 (1) ◽  
pp. 84-91 ◽  
Author(s):  
J. N. Chung ◽  
D. L. R. Oliver
Keyword(s):  
Heat Transfer ◽  
Electric Field ◽  
Dielectric Medium ◽  
Internal Motion ◽  
Creeping Flow ◽  
Transient Heat Transfer ◽  
Fluid Sphere ◽  
Minor Importance ◽  
Flow Strength ◽  
Induced Flow

The transient heat transfer in a fluid sphere translating steadily in a dielectric medium is numerically investigated. The energy equation with velocity components of combined translation-induced and electric field-induced internal motion is integrated by the Alternating Direction Implicit (ADI) method for the entire drop interior. Creeping flow is assumed and the preponderance of the thermal resistance is assumed completely in the dispersed phase. The enhancement of heat transfer due to internal motion induced by both drop translation and the electric field is given in terms of the Nusselt number. Nusselt numbers are plotted as a function of the Fourier number, the Peclet number, and a parameter E. The parameter E represents the ratio of electric field-induced flow strength to that of translation-induced flow. In general, the heat transfer rate is approximately doubled when the flow is dominated by the electric field as compared with the case where no electric field is applied. It is suggested that for large Peclet numbers, the electric field is negligible for E less than 0.5, while the translation is unimportant for E larger than 10. For small Peclet numbers, the electric field is of minor importance for E less than 2 and the translation is insignificant for E greater than 50.

Effect of Quincke Rotation and Taylor Circulation on Mass Transfer from a Fluid Drop in a Constant Electric Field

2011 ◽  
Vol 312-315 ◽  
pp. 259-264
Author(s):  
Tov Elperin ◽  
A. Fominykh
Keyword(s):  
Mass Transfer ◽  
Electric Field ◽  
Similarity Transformation ◽  
Constant Electric Field ◽  
Analytical Form ◽  
Uniform Electric Field ◽  
Two Dimensional ◽  
Convective Mass Transfer ◽  
Fluid Drop ◽  
Quincke Rotation

We consider non-stationary convective mass transfer in a binary system comprising a stationary dielectric two-dimensional fluid drop embedded into an immiscible dielectric liquid under the influence of a constant uniform electric field. The partial differential equation of diffusion is solved by means of a similarity transformation, and the solution is obtained in a closed analytical form. Dependence of Sherwood number vs. the strength of the applied electric field is analyzed. It is shown that an electric field can be used for enhancement of the rate of mass transfer in terrestrial and reduced gravity environments.

Transient Heat and Mass Transfer to a Drop in an Electric Field

1977 ◽  
Vol 99 (2) ◽  
pp. 269-273 ◽  
Author(s):  
F. A. Morrison
Keyword(s):  
Mass Transfer ◽  
Electric Field ◽  
Transfer Rate ◽  
Similarity Transformation ◽  
Fluid Motion ◽  
Sudden Change ◽  
Drop Surface ◽  
Concentration Difference ◽  
Boundary Layer Equations ◽  
Surrounding Fluid

A circulating fluid motion is generated by an electric field imposed on a dielectric drop in another dielectric liquid. The motion of the drop surface may be from the poles to the equator or from the equator to the poles. Transient heat or mass transfer results in response to a sudden change in the temperature difference or concentration difference between the drop and the surrounding fluid. The low Reynolds number, high Peclet number response is analyzed. The boundary layer equations are solved exactly using a similarity transformation. Results are obtained for both directions of circulation. While local fluxes differ greatly when the flow reverses, and despite a lack of symmetry, the overall transfer rate is independent of the direction of flow. This result applies to the transient as well as the steady state.

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