کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
662041 1458160 2007 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Flow boiling heat transfer characteristics of nitrogen in plain and wire coil inserted tubes
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Flow boiling heat transfer characteristics of nitrogen in plain and wire coil inserted tubes
چکیده انگلیسی

Boiling heat transfer characteristics of nitrogen were experimentally investigated in a stainless steel plain tube and wire coil inserted tubes. Wire coils having different coil pitches and wire thicknesses were inserted into a horizontally positioned plain tube, which had an inner diameter of 10.6 mm and a length of 1.65 m. The coil pitches were 18.4, 27.6, and 36.8 mm, and the wire thicknesses were 1.5, 2.0, and 2.5 mm. Tests were conducted at a saturation temperature of −191 °C, mass fluxes from 58 to 105 kg/m2 s, and heat fluxes from 22.5 to 32.7 kW/m2. A direct heating method was used to apply heat to the test tube. The boiling heat transfer coefficients of nitrogen significantly decreased when the dryout occurred. Enhancement performance ratio (EPR), which is the ratio of heat transfer enhancement factor to pressure drop ratio, was used to evaluate the performance of the wire coil inserts. The maximum heat transfer enhancement of the wire coil inserted tubes over the plain tube was 174% with wire 3 having a twist ratio (p/Dw) of 1.84 and a thickness ratio (t/Dw) of 0.25. Wire 3-inserted tube showed the highest EPR among the tested tubes in this study.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 50, Issues 11–12, June 2007, Pages 2339–2345
نویسندگان
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