کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
7052450 1457417 2014 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Flow boiling characteristics of R-245fa in a minichannel at medium saturation temperatures
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Flow boiling characteristics of R-245fa in a minichannel at medium saturation temperatures
چکیده انگلیسی
This paper presents new experimental results concerning thermohydraulic characteristics of flow boiling at medium saturation temperatures. The experimental results were obtained in a horizontal 3.0 mm inner tube diameter with R-245fa as working fluid. The mass velocity ranged from 100 to 1500 kg/m2 s, the heat flux from 10kW/m2 to 90kW/m2, the saturation temperature from 60 °C to 80 °C and the vapor quality from 0 to 1. Four flow patterns are likely to appear in these conditions: intermittent flow, annular flow, dry-out flow and mist flow. Heat transfer coefficients were measured and parametric analyses were performed on the effect of heat flux, mass velocity and saturation temperature on the local heat transfer coefficient. At 60 °C and 80 °C, the heat transfer coefficient is independent from vapor quality and mass velocity during intermittent flow whereas it is sensitive to heat flux. In annular flow, the heat transfer coefficient increases with increasing vapor quality and/or mass velocity. As a result, nucleate and convective boiling are both present. The pre-dryout database of 3070 data points is compared against several predictive methods from the literature. These comparisons are an extrapolation to test the validity of the prediction methods at medium saturation temperature in minichannels.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Experimental Thermal and Fluid Science - Volume 59, November 2014, Pages 184-194
نویسندگان
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