RESEARCH PAPERS: Heat Exchangers

A Model for Condensate Retention on Plain-Fin Heat Exchangers

[+] Author and Article Information
A. I. ElSherbini2

Building and Energy Technologies Department, Kuwait Institute for Scientific Research, P.O. Box 24885 Safat, 13109, Kuwaitasherbini@kisr.edu.kw

A. M. Jacobi

Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 1206 W. Green St., Urbana, IL 61801a-jacobi@uiuc.edu

The receding contact angle, θR, is not required, but can be incorporated—if know—into calculating Dmax.


Corresponding author.

J. Heat Transfer 128(5), 427-433 (Oct 19, 2005) (7 pages) doi:10.1115/1.2175091 History: Received January 23, 2005; Revised October 19, 2005

A model has been developed for predicting the amount of condensate retained as drops on the air-side of heat exchangers operating under dehumidifying conditions. For a coil with a given surface wettability, characterized by the advancing contact angle, the maximum diameter for a retained drop is obtained from a balance between gravitational and surface tension forces. A logarithmic function is used to describe the size-distribution of drops on fins, based on the fraction of fin-area covered by liquid. The volumes of individual drops are calculated by a geometric method for approximating the three-dimensional shapes of drops on vertical and inclined surfaces. The total volume of condensate accumulated on a coil is then found by multiplying the size-distribution and volume functions and integrating over all drop diameters. The model is successful in predicting measurements by other researchers of the mass of condensate retained on plain-fin heat exchangers. The critical fin spacing to avoid the formation of condensate bridges is also predicted.

Copyright © 2006 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 1

(a) Profile of a liquid drop fit by parts of two circles. (b) Contact line at the base of the drop. The two-circle method approximates the profiles and volumes of drops on vertical or inclined fins.

Grahic Jump Location
Figure 2

Minimum contact angle, normalized by the maximum angle, as it varies with the Bond number for different liquids and surfaces. A single relation fits the data with a coefficient of determination r2=0.90.

Grahic Jump Location
Figure 3

A force balance on a drop on an inclined fin, used to find the maximum drop diameter

Grahic Jump Location
Figure 4

Size-distribution functions for drops condensing on plane surfaces, obtained by different researchers

Grahic Jump Location
Figure 5

Heat-exchanger geometry used for comparing the model to measurements of retained condensate

Grahic Jump Location
Figure 6

Predicted mass of condensate retained on heat exchangers compared to measurements reported by Shin and Ha (27) and Korte and Jacobi (6), and to an earlier model

Grahic Jump Location
Figure 7

Critical fin spacing, beyond which condensate bridges cannot occur, as a function of the advancing contact angle



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