Estudo experimental da perda de pressão em escoamento com ebulição convectiva para a mistura zeotrópica R-407C

Abstract

The present work is a theoretical and experimental study on the pressure drop of the refrigerant R-407C in convective boiling. This fluid is a mixture zeotropic that is little aggressive to the environment. This fluid is one of the possible replacements fluids for the R-22 used in refrigeration and heating vapor compression systems. In this work, a careful review of the literature involving flow patterns maps and the main methods for estimating pressure drop in two-phase flow was conducted. Experimental results to pressure drop of the R-407C were collected into tubes with 4,5 mm and 8,0 mm internal diameter and compared to 17 predictive methods found in the literature. After performing this comparative study, 5 correlation were selected: Cicchitti, Sun and Mishima, Müller-Steinhagen and Heck, McAdams, Woods and Heroman, and Xu and Fang. Finally, a new method for predicting pressure drop for refrigerant R-407C was proposed based on the correlation of Bandarra Filho Jabardo and Barbieri, which was satisfactory, with mean absolute relative error of 27,9% and providing 90 % of the experimental results with less than 45% error.