EXPERIMENTAL STUDY ON TWO-PHASE FLOW PRESSURE DROP IN COPPER TUBE BENDS FOR THE ZEOTROPIC BLEND R-407C

Ludgero Damasceno Junior¹; Juan José Garcia¹; Leandro Cristino Oliveira Pereira¹; Matheus Pereira Porto¹; Luiz Machado¹

¹ Universidade Federal de Minas Gerais

doi:10.20906/CPS/COB-2015-0405

Resumo

Evaporators and condensers of modern cooling systems are becoming increasingly compact, and as a consequence the heat exchangers are presenting larger numbers of return bends. Due to this fact, minor losses as return bends become more important on the system performance. In this work, a test bench was used to study the pressure drop in return bends, with a tube diameter (D) of 4.77 mm and the curvature ratio (2R/D) from 4,40 to 10.83. The experimental data set is obtained varying the refrigerant mass flux within the range from 100 kgm-2s-1 to 600 kgm-2s-1, and a saturated pressure of 12 bar. The goal of this work is to collect experimental data for the blend R-407C flowing in return bends and compare the experimental values against theoretical correlations. It was observed that the Padilla correlation showed the best results.

Palavras-chave: Return bends; R-407C; Two-phase flow; Pressure drop