Доступ предоставлен для: Guest
Портал Begell Электронная Бибилиотека e-Книги Журналы Справочники и Сборники статей Коллекции
Journal of Enhanced Heat Transfer
Импакт фактор: 0.562 5-летний Импакт фактор: 0.605 SJR: 0.175 SNIP: 0.361 CiteScore™: 0.33

ISSN Печать: 1065-5131
ISSN Онлайн: 1026-5511

Том 27, 2020 Том 26, 2019 Том 25, 2018 Том 24, 2017 Том 23, 2016 Том 22, 2015 Том 21, 2014 Том 20, 2013 Том 19, 2012 Том 18, 2011 Том 17, 2010 Том 16, 2009 Том 15, 2008 Том 14, 2007 Том 13, 2006 Том 12, 2005 Том 11, 2004 Том 10, 2003 Том 9, 2002 Том 8, 2001 Том 7, 2000 Том 6, 1999 Том 5, 1998 Том 4, 1997 Том 3, 1996 Том 2, 1995 Том 1, 1994

Journal of Enhanced Heat Transfer

DOI: 10.1615/JEnhHeatTransf.v6.i2-4.110
pages 217-236

A Critical Review of Condensation Heat Transfer Predicting Models-Effects of Surface-tension Force

Chien-Yuh Yang
National Central University

Краткое описание

Condensation is defined as the transformation of vapor to its liquid state. Gravity and vapor shear are the two forces that drive the flow of the condensate film inside plain tubes. Traditional condensation predicting models generally include the effects of these two forces. For finned tubes, the surface-tension force will also be important. This paper provides a critical review of existed predicting models to correlate condensation heat transfer coefficients. Gravity-force dominated models, vapor-shear dominated models and the effects of surface-tension force are all discussed. Three basic methods have been used to model the vapor-shear dominated annular liquid film. The first model assumed that the vapor core could be replaced with an equivalent liquid flow that would yield the same value for the vapor shear. The second model assumed that the major resistance to heat transfer was offered only by the laminar liquid sublayer. The third model assumed that the velocity in liquid film could be predicted using von Karman universal velocity profile.
Yang and Webb (1997) study shows that at low-mass-velocity and high-vapor-quality conditions, the effect of surface tension is comparable to that of vapor shear for condensation heat transfer inside a micro-fin tube with 13 μm fin tip radius. Owing to the manufacturing technology development of integrated circuits, smaller tubes and fin geometries can be made and used for increasing the condensation heat transfer coefficient. Because the surface-tension drainage force is proportional directly to the inverse of fin-tip radius, the importance of the surface-tension effect will increase with the development of micro-fabrication technology. The Yang and Webb (1997) model is the first model that accounts for the effects of vapor and surface-tension forces simultaneously. However, their database did not cover wide range of fluid properties and fin geometries. More work is needed on correlation and theoretically based models.