کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1728783 1521145 2013 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Forced convective and subcooled flow boiling heat transfer to pure water and n-heptane in an annular heat exchanger
موضوعات مرتبط
مهندسی و علوم پایه مهندسی انرژی مهندسی انرژی و فناوری های برق
پیش نمایش صفحه اول مقاله
Forced convective and subcooled flow boiling heat transfer to pure water and n-heptane in an annular heat exchanger
چکیده انگلیسی

In this research, subcooled flow boiling heat transfer coefficients of pure n-heptane and distilled water at different operating conditions have been experimentally measured and compared. The heat exchanger consisted of vertical annulus which is heated from the inner cylindrical heater with variable heat flux (less than 140 kW/m2). Heat flux is varied so that two different flow regimes from single phase forced convection to nucleate boiling condition are created. Meanwhile, liquid flow rate is changed in the range of 2.5 × 10−5–5.8 × 10−5 m3/s to create laminar up to transition flow regimes. Three subcooling levels including 10, 20 and 30 °C are also considered. Experimental results demonstrated that subcooled flow boiling heat transfer coefficient increases when higher heat flux, higher liquid flow rate and greater subcooling level are applied. Furthermore, influence of the operating conditions on the bubbles generation on the heat transfer surface is also discussed. It is also shown that water is better cooling fluid in comparison with n-heptane.


► The cooling performance of water and n-heptane is compared during subcooled flow boiling.
► Although n-heptane leaves the heat exchanger warmer it has a lower heat transfer coefficient.
► Flow rate, heat flux and degree of subcooling have direct effect on heat transfer coefficient.
► The predictions of some correlations are evaluated against experimental data.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Annals of Nuclear Energy - Volume 53, March 2013, Pages 401–410
نویسندگان
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