کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
658899 1458096 2012 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Examination of minimum-heat-flux-point condition for film boiling on a sphere in terms of the limiting liquid superheat and the critical vapor film thickness
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Examination of minimum-heat-flux-point condition for film boiling on a sphere in terms of the limiting liquid superheat and the critical vapor film thickness
چکیده انگلیسی

Previously proposed theories of the minimum-heat-flux-point (MHF-point) condition were examined using available experimental data obtained from the immersion cooling of spheres in water. The sphere diameter ranged from 9.5 to 30 mm and the liquid subcooling from 0 to 85 K. The limiting liquid superheat predicted by the Lienhard equation was compared with the liquid–solid interface superheat at the instant of liquid–solid contact at the MHF-point. The results showed that the liquid–solid interface superheat was not limited by the limiting liquid superheat and its value was connected with the collapse mode of vapor film. The collapse mode was a coherent collapse at a low interface superheat and the mode changed to a propagative collapse as the interface superheat increased. The critical vapor film thickness obtained from the linear stability analysis of vapor film was compared with the calculated value of average vapor film thickness at the MHF-point. For all data, the ratio of the average vapor film thickness to the critical vapor film thickness was correlated well as a function of liquid subcooling. The ratio decreased with increasing liquid subcooling and tended to about 0.8 to 1 depending on the experiments. This indicated that the MHF-point at a high liquid subcooling was determined by the critical vapor film thickness. A physical consideration was given to the effect of liquid–solid contact that occurred in the film boiling region on the calculated value of the vapor film thickness and the stability of vapor film.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 55, Issues 9–10, April 2012, Pages 2377–2383
نویسندگان
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