کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
668972 | 1458789 | 2010 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Pool boiling heat transfer on copper foam covers with water as working fluid
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Pool boiling heat transfer with porous media as the enhanced structure is attractive due to its simple geometry and easy operation. However, the available studies focus on low porous porosities. Metallic foams provide large porous porosities that have been less studied in the literature. In this paper a set of copper foam pieces were welded on the plain copper surface to form the copper foam covers for the pool boiling heat transfer enhancement. Water was used as the working fluid. Enhancement of pool boiling heat transfer compared with plain surface depends on the increased bubble nucleation sites, extended heat transfer area, and resistance for vapor release to the pool liquid. Effects of pores per inch (ppi) of foam covers, foam cover thickness, and pool liquid temperatures are examined. It is found that temperatures at the Onset of Nucleate Boiling (ONB) are significantly decreased on copper foam covers compared with on plain surfaces. Heat transfer coefficients of foam covers are two to three times of the plain surface. A large ppi value provides large bubble nucleation sites and heat transfer area to enhance heat transfer, but generates large vapor release resistance to deteriorate heat transfer. Therefore an optimal ppi value exists, which is 60Â ppi in this paper. Generally small ppi value needs large foam cover thickness, and large ppi value needs small foam cover thickness, to maximally enhance heat transfer. Effect of pool liquid temperature on the heat transfer enhancement depends on the ppi value. For small ppi value such as 30Â ppi, lower pool liquid temperature can dissipate higher heat flux at the same wall superheat. However, the heat transfer performance is insensitive to the pool liquid temperatures when large ppi values such as 90Â ppi are used.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Thermal Sciences - Volume 49, Issue 7, July 2010, Pages 1227-1237
Journal: International Journal of Thermal Sciences - Volume 49, Issue 7, July 2010, Pages 1227-1237
نویسندگان
Yongping Yang, Xianbing Ji, Jinliang Xu,