Low péclét number mass transfer in laminar flow through circular tubes

The problem of convective diffusion toward the sphere in laminar flow around the sphere is solved by combination of the analytical and net methods for the region of Peclet number λ ≥ 1. The problem was also studied for very small values λ. Stability of the solution has been proved in relation to changes of the velocity profile.

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A variational approach to low peclet number heat transfer in laminar flow

Journal of Computational Physics ◽

10.1016/0021-9991(72)90019-8 ◽

1972 ◽

Vol 9 (2) ◽

pp. 207-221 ◽

Cited By ~ 16

Author(s):

J.C Pirkle ◽

V.G Sigillito

Keyword(s):

Heat Transfer ◽

Laminar Flow ◽

Peclet Number ◽

Variational Approach ◽

Péclet Number

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Concentration Distribution in the Wake of a Plane Surface Buried in a Porous Media in Alignment with the Flow Direction

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.283-286.553 ◽

2009 ◽

Vol 283-286 ◽

pp. 553-558

Author(s):

João M.P.Q. Delgado ◽

M. Vázquez da Silva

Keyword(s):

Mass Transfer ◽

Peclet Number ◽

Numerical Solutions ◽

Plane Surface ◽

Flow Direction ◽

Mathematical Expression ◽

Mass Conservation ◽

Mass Transfer Process ◽

Packed Bed ◽

Péclet Number

The present work describes the mass transfer process between a moving fluid and a slightly soluble flat surface buried in a packed bed of small inert particles with uniform voidage, by both advection and diffusion. Numerical solutions of the differential equation describing solute mass conservation were undertaken to obtain the concentration profiles, for each concentration level, the width and downstream length of the corresponding contour surface and the mass transfer flux was integrated to give the Sherwood number as a function of Peclet number. A mathematical expression that relates the dependence with the Peclet number is proposed to describe the approximate size of the diffusion wake downstream of the reactive solid mass.

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Analysis of Laminar Slip-Flow Thermal Transport in Microchannels With Transverse Rib and Cavity Structured Superhydrophobic Walls at Constant Heat Flux

ASME/JSME 2011 8th Thermal Engineering Joint Conference ◽

10.1115/ajtec2011-44113 ◽

2011 ◽

Cited By ~ 1

Author(s):

D. Maynes ◽

B. W. Webb ◽

V. Soloviev

Keyword(s):

Heat Flux ◽

Nusselt Number ◽

Laminar Flow ◽

Thermal Transport ◽

Peclet Number ◽

Average Nusselt Number ◽

Slip Flow ◽

Constant Heat Flux ◽

Constant Heat ◽

Péclet Number

This paper presents an analytical investigation of the thermally developing and periodically fully-developed flow in a parallel-plate channel comprised of superhydrophobic walls. The superhydrophobic walls considered in this paper exhibit alternating micro-ribs and cavities positioned perpendicular to the flow direction and the transport scenario analyzed is that of constant wall heat flux through the rib surfaces with negligible thermal transport through the vapor cavity interface. Axial conduction is neglected in the analysis and the problem is one of Graetz flow with apparent slip-flow and periodicity of constant heating. Closed form solutions for the local Nusselt number and wall temperature are presented and are in the form of infinite series expansions. Previously it has been shown that significant reductions in the overall frictional pressure drop can be expected relative to the classical smooth channel laminar flow. The present results reveal that the overall thermal transport is markedly influenced by the relative cavity region (cavity fraction), the relative rib/cavity module width, and the flow Peclet number. The following conclusions can be made regarding thermal transport for a constant heat flux channel exhibiting the superhydrophobic surfaces considered: 1) Increases in the cavity fraction lead to decreases in the average Nusselt number; 2) Increasing the relative rib/cavity module length yields a decrease in the average Nusselt number; and 3) as the Peclet number increases the average Nusselt number increases. For all parameters explored, the limiting upper bound on the fully-developed average Nusselt number corresponds to the limiting case scenario of classical laminar flow through a smooth-walled channel with constant heat flux.

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