Experimental investigation on flow boiling heat transfer in conventional and mini vertical channels

An experimental investigation was carried out to study the flow boiling heat transfer mechanism in the vertical channels with different inner diameters. The heating section of the test-section was stainless steel tube, and the transparent sections were equipped at inlet and outlet of the test-section, respectively. The flow patterns at outlet were recorded by a high speed camera, and the corresponding experimental parameters were measured simultaneously. In this study, the characteristics of flow boiling heat transfer with different inner diameters, inlet water temperatures, mass fluxes, and heat fluxes were analyzed in detail. Moreover, a modified correlation on the Chen correlation was proposed to predict the heat transfer coefficients in the vertical channels, and this correlation was verified with good agreement.