0
Research Papers

Effect of Tube Geometry and Curvature on Film Condensation in the Presence of a Noncondensable Gas

[+] Author and Article Information
Huijun Li

School of Energy Power and
Mechanical Engineering,
North China Electric Power University,
Box 27, No. 619 Yonghua North Road,
Baoding 071003, China
e-mail: hj_li009@sina.com

Wenping Peng

School of Energy Power and
Mechanical Engineering,
North China Electric Power University,
e-mail: wenpingpeng@gmail.com

Yingguang Liu

School of Energy Power and
Mechanical Engineering,
North China Electric Power University,
e-mail: yingguang266@126.com

Chao Ma

School of Energy Power and
Mechanical Engineering,
North China Electric Power University,
e-mail: 569242650@qq.com

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS. Manuscript received January 12, 2014; final manuscript received June 17, 2014; published online September 16, 2014. Assoc. Editor: Mehmet Arik.

J. Thermal Sci. Eng. Appl 7(1), 011001 (Sep 16, 2014) (9 pages) Paper No: TSEA-14-1010; doi: 10.1115/1.4028345 History: Received January 12, 2014; Revised June 17, 2014

Based on the double boundary layer theory, a generalized mathematical model was developed to study the distributions of gas film, liquid film, and heat transfer coefficient along the tube surface with different geometries and curvatures for film condensation in the presence of a noncondensable gas. The results show that: (i) for tubes with the same geometry, gas film thickness, and liquid film thickness near the top of the tube decrease with the increasing of curvature and the heat transfer rate increases with it. (ii) For tubes with different geometries, one need to take into account all factors to compare their overall heat transfer rate including gas film thickness, liquid film thickness and the separating area. Besides, the mechanism of the drainage and separation of gas film and liquid film was analyzed in detail. One can make a conclusion that for free convection, gas film never separate since parameter A is always positive, whereas liquid film can separate if parameter B becomes negative. The separating angle of liquid film decreases with the increasing of curvature.

FIGURES IN THIS ARTICLE
<>
Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Condensing surfaces with different geometries. (a) A horizontal ellipse and (b) an equiangular spiral curve.

Grahic Jump Location
Fig. 2

Physical model and coordinate system of the circular one

Grahic Jump Location
Fig. 3

Calculation scheme flowchart

Grahic Jump Location
Fig. 4

The distributions of gas film, liquid film, and heat transfer coefficient along the tube surface with different e for an elliptical tube. (a) Gas film thickness, (b) liquid film thickness, and (c) heat transfer coefficient.

Grahic Jump Location
Fig. 5

The distributions of gas film, liquid film, and heat transfer coefficient along the tube surface with different m for an equiangular spiral tube. (a) Gas film thickness, (b) liquid film thickness, and (c) heat transfer coefficient.

Grahic Jump Location
Fig. 6

The distributions of gas film, liquid film, and heat transfer coefficient along the tube surface for an equiangular spiral tube and an elliptical tube. (a) Gas film thickness, (b) liquid film thickness, and (c) heat transfer coefficient.

Grahic Jump Location
Fig. 7

The average heat transfer coefficients for different tube geometries and curvatures with bulk concentration of noncondensable gas in the condition of liquid film nonseparating

Grahic Jump Location
Fig. 8

The distributions of the parameters related to the discharge and separation along the tube surface (a) for an elliptical tube and (b) for an equiangular spiral tube

Grahic Jump Location
Fig. 9

Comparison of average heat transfer coefficient between the present model and the data from Tang et al. [11] for a circular tube

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