Condensation heat transfer in square, triangular, and semi-circular mini-channels

0017-9310/$ see front matter 2011 Elsevier Ltd. A doi:10.1016/j.ijheatmasstransfer.2011.09.002 ⇑ Corresponding author. Address: JEC 2049 2nd Institute, 110 8th St., Troy, NY 12180, United States. +1 518 276 6025. E-mail address: [email protected] (M.K. Jensen). Condensation heat transfer coefficients in mini-channels were measured with smaller measurement uncertainties than previously obtained using three specially designed copper test sections. Single-phase experiments validated the approach. Data are reported for R134a in 1 mm square, triangular, and semicircular multiple parallel minichannels cooled on three sides. A parametric study was conducted over a range of conditions for mass flux, average quality, saturation pressure, and heat flux. Mass flux and quality were determined to have significant effects on the condensation process, even at lower mass fluxes, while saturation pressure, heat flux, and channel shape had no significant effects. The lack of shape effects were attributed to the three-sided cooling boundary conditions. Because there was no significant surface tension enhancement, the macro-scale Shah (2009) [26] correlation best predicted the data, with a mean average error (MAE) of 20–30% for all geometries. 2011 Elsevier Ltd. All rights reserved.