کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
789727 1466455 2010 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Measurement and modeling of condensation heat transfer in non-circular microchannels
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی مکانیک
پیش نمایش صفحه اول مقاله
Measurement and modeling of condensation heat transfer in non-circular microchannels
چکیده انگلیسی

Heat transfer coefficients in six non-circular horizontal microchannels (0.424 < Dh < 0.839 mm) of different shapes during condensation of refrigerant R134a over the mass flux range 150 < G < 750 kg m−2 s−1 were measured in this study. The channels included barrel-shaped, N-shaped, rectangular, square, and triangular extruded tubes, and a channel with a W-shaped corrugated insert that yielded triangular microchannels. The thermal amplification technique developed and reported in earlier work by the authors is used to measure the heat transfer coefficients across the vapor-liquid dome in small increments of vapor quality. Results from previous work by the authors on condensation flow mechanisms in microchannel geometries were used to interpret the results based on the applicable flow regimes. The effect of tube shape was also considered in deciding the applicable flow regime. A modified version of the annular-flow-based heat transfer model proposed recently by the authors for circular microchannels, with the required shear stress being calculated from a non-circular microchannel pressure drop model also reported earlier was found to best correlate the present data for square, rectangular and barrel-shaped microchannels. For the other microchannel shapes with sharp acute-angle corners, a mist-flow-based model from the literature on larger tubes was found to suffice for the prediction of the heat transfer data. These models predict the data significantly better than the other available correlations in the literature.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Refrigeration - Volume 33, Issue 6, September 2010, Pages 1169–1179
نویسندگان
, , ,