Prediction of Condensation Heat Transfer Coefficient based on the Flow Pattern inside 4 mm Microfin Small-Diameter Tubes

Abstract

In this paper, we classified into an annular region dominated by forced convection condensation and a wavy-slag region dominated by free convection condensation based on changes in flow pattern, using the experimental values of R123ze(E), R410A, R32 and R152a of previously paper (Hirose et al. 2019 and Hirose et al. 2018). Based on them, by detailed consideration for the effect of each mass velocity in annular flow region of the small-diameter tubes and surface tension due to tube diameter reduction in wavy-slag flow region on condensation heat transfer, we optimized the predicted correlation of condensation heat transfer coefficient for microfin small-diameter tubes. The optimized predicted correlation can be estimated within 30% our experimental values, and the tendency of other researchers’ experimental values, also the condensation heat transfer coefficient of 4 mm microfin small-diameter tubes for various refrigerants and fin geometries.