The effect of gravity on R410A condensing flow in horizontal circular tubes
Author(s)
Type
Journal Article
Abstract
Heat transfer characteristics of R410A condensation in horizontal tubes with the inner diameter of 3.78 mm under normal and reduced gravity are investigated numerically. The results indicate that the heat transfer coefficients increase with increasing gravitational accelerations at a lower mass flux, whereas their differences under varying gravity are insignificant at a higher mass flux. The liquid film thickness decreases with increasing gravity at the top part of the tube, whereas the average liquid film thickness is nearly the same under different gravity accelerations at the same vapor quality and mass flux. The local heat transfer coefficients increase with increasing gravity at the top of the tube and decrease with increasing gravity at the bottom. The proportion of the thin liquid film region is important for the overall heat transfer coefficients for the condensing flow. A vortex with its core lying at the bottom of the tube is observed under normal gravity because of the combined effect of gravity and the mass sink at the liquid–vapor interface, whereas the stream traces point to the liquid–vapor interfaces under zero gravity. The mass transfer rate under zero gravity is much lower than that of normal gravity.
Date Issued
2017-02-13
Date Acceptance
2016-11-04
Citation
Numerical Heat Transfer Part A: Applications, 2017, 70 (3), pp.327-340
ISSN
1040-7782
Start Page
327
End Page
340
Journal / Book Title
Numerical Heat Transfer Part A: Applications
Volume
70
Issue
3
Copyright Statement
© 2017 Taylor & Francis. This is an Accepted Manuscript of an article published by Taylor & Francis in Numerical Heat Transfer, Part A: Applications on 13 Feb 2017, available online: http://www.tandfonline.com/doi/full/10.1080/10407782.2016.1264743
Subjects
Mechanical Engineering & Transports
0102 Applied Mathematics
0905 Civil Engineering
0913 Mechanical Engineering
Publication Status
Published