کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
7046995 1457121 2016 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Evaporation heat transfer and pressure drop characteristics of R-600a in horizontal smooth and helically dimpled tubes
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Evaporation heat transfer and pressure drop characteristics of R-600a in horizontal smooth and helically dimpled tubes
چکیده انگلیسی
An experimental investigation was performed to evaluate the heat transfer and pressure drop characteristics of the hydrocarbon refrigerant R-600a during flow boiling inside a horizontal smooth tube with an inside diameter of 8.25 mm and a newly developed dimpled tube. The inner surface of the helically dimpled tube is enhanced by a newly modified pattern consists of both shallow and deep protrusions. The experimental tests were carried out varying: the refrigerant mass fluxes within the range of 155-470 kg/m2 s; the vapor qualities up to 0.8; the constant heat flux of 15.8 kW/m2 and saturation temperature of 56.5 °C. Observations clearly indicate that the heat transfer performance is improved as tube's inner surface enhanced by this new pattern of protrusions. The experimental results show that the heat transfer coefficients of the dimpled tube are 1.29-2 times larger than a smooth tube with a pressure drop just ranging between 7% and 103% larger than the smooth tube. The highest enhancement in the heat transfer coefficient occurs at vapor quality of 0.2 and mass flow rate of 155 kg/m2 s. On the other hand, the maximum increase of pressure drop takes place at vapor quality of 0.8 and mass flow rate of 305 kg/m2 s.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Thermal Engineering - Volume 107, 25 August 2016, Pages 28-36
نویسندگان
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