کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
649751 1457222 2005 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Start-up from the frozen state of two-phase thermosyphons
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Start-up from the frozen state of two-phase thermosyphons
چکیده انگلیسی

In a cold region, ethylene glycol or propylene glycol aqueous solution is usually used as a working fluid of thermosyphons, because if pure water is used as a working fluid, the thermosyphon tube breaks due to the volume expansion of ice when water freezes into ice. If a non-freeze working fluid is required, for example, under the environmental temperature of −20 °C, around 37 mass% ethylene glycol aqueous solution must be used. Usually, two-phase heat transfer coefficients of binary mixtures become lower than pure liquid. As the concentration of ethylene glycol increases, the freezing point lowers, and then the heat transfer coefficient also lowers. Therefore, if the small concentration of ethylene glycol is used, the degradation in heat transfer may be small. In the present study, 1–40 mass% ethylene glycol aqueous solutions were prepared, and they were poured into glass test tubes, respectively. These glass test tubes were immersed in ethanol of −20 °C to −40 °C, which were cooled down by a refrigerator. Consequently, the test tube with pure water was cracked and broken, but the other test tubes were not broken even in the case of 1 mass% concentration. Since the above fact was found, the start-up experiment from the frozen state of the two-phase thermosyphon was carried out using 1 and 2 mass% ethylene glycol aqueous solutions as the working fluid. As a result, it was revealed that these thermosyphons started up smoothly without any troubles.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Thermal Engineering - Volume 25, Issues 17–18, December 2005, Pages 2730–2739
نویسندگان
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