0
Research Papers

Numerical Modeling of the Conjugate Heat Transfer Problem for Annular Laminar Film Condensation in Microchannels

[+] Author and Article Information
Stefano Nebuloni1

 Laboratory of Heat and Mass Transfer (LTCM),Swiss Federal Institute of Technology,Lausanne (EPFL), Lausanne CH-1015, Switzerlandstefano.nebuloni@epfl.ch

John R. Thome

 Laboratory of Heat and Mass Transfer (LTCM),Swiss Federal Institute of Technology,Lausanne (EPFL), Lausanne CH-1015, Switzerlandstefano.nebuloni@epfl.ch

1

Corresponding author.

J. Heat Transfer 134(5), 051021 (Apr 13, 2012) (7 pages) doi:10.1115/1.4005712 History: Received August 11, 2010; Revised August 21, 2011; Published April 11, 2012; Online April 13, 2012

This paper presents numerical simulations of annular laminar film condensation heat transfer in microchannels of different internal shapes. The model, which is based on a finite volume formulation of the Navier–Stokes and energy equations for the liquid phase only, importantly accounts for the effects of axial and peripheral wall conduction and nonuniform heat flux not included in other models so far in the literature. The contributions of the surface tension, axial shear stresses, and gravitational forces are included. This model has so far been validated versus various benchmark cases and versus experimental data available in literature, predicting microchannel heat transfer data with an average error of 20% or better. It is well known that the thinning of the condensate film induced by surface tension due to gravity forces and shape of the surface, also known as the “Gregorig” effect, has a strong consequence on the local heat transfer coefficient in condensation. Thus, the present model accounts for these effects on the heat transfer and pressure drop for a wide variety of geometrical shapes, sizes, wall materials, and working fluid properties. In this paper, the conjugate heat transfer problem arising from the coupling between the thin film fluid dynamics, the heat transfer in the condensing fluid, and the heat conduction in the channel wall has been studied. In particular, the work has focused on three external channel wall boundary conditions: a uniform wall temperature, a nonuniform wall heat flux, and single-phase convective cooling are presented. As the scale of the problem is reduced, i.e., when moving from mini- to microchannels, the results show that the axial conduction effects can become very important in the prediction of the wall temperature profile and the magnitude of the heat transfer coefficient and its distribution along the channel.

FIGURES IN THIS ARTICLE
<>
Copyright © 2012 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 7

Condensate film profile along the channel and local vapor qualities X at different distances for the elliptical shape channel and a uniform Tw distribution

Grahic Jump Location
Figure 8

Perimeter averaged wall temperature profiles plotted as a function of the dimensionless axial location for the elliptical shape channel for different boundary conditions

Grahic Jump Location
Figure 9

Local vapor quality plotted versus the dimensionless axial location for the elliptical channel and three different wall boundary conditions

Grahic Jump Location
Figure 10

Perimeter averaged heat transfer coefficient plotted as a function of the local vapor quality for the elliptical channel and for different coolant side temperature variations

Grahic Jump Location
Figure 11

Dimensionless temperature profile versus dimensionless location for the elliptical channel for different coolant side temperature variations

Grahic Jump Location
Figure 6

Perimeter averaged heat transfer coefficient plotted versus the dimensionless axial location for the flattened shape channel

Grahic Jump Location
Figure 5

Perimeter averaged wall temperature profiles plotted as a function of the dimensionless axial location for the flattened shape channel

Grahic Jump Location
Figure 4

Local film thickness along the channel surface at different dimensionless curvilinear coordinates as a function of the dimensionless axial position Z for the flattened shape channel and a uniform wall temperature distribution

Grahic Jump Location
Figure 3

Local film thickness along the channel surface at different distances as a function of the dimensionless curvilinear coordinate for the flattened shape channel and a uniform wall temperature distribution

Grahic Jump Location
Figure 2

Condensate film profile along the channel and local vapor qualities at different distances for the flattened shape channel and a uniform wall temperature distribution

Grahic Jump Location
Figure 1

Dimensionless heat flux distributions versus the reduced dimensionless axial location

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In