Mathematical modeling of the ester oil-refrigerant R134a mixture two-phase flow with foam formation through a small diameter tube

Abstract

This work presents a mathematical modeling to study the ester oil ISO VG-10-refrigerant R134a mixture two-phase flow with foam formation through a 3.22 mm ID tube. Based on experimental visualization results, the flow is divided into three regions: a single phase flow at the inlet of the tube; an intermediary bubbly flow region; and a foam flow region at the end of the tube. Numerical results for mass flow rate, pressure and temperature distributions along the flow were compared with experimental data available in literature, showing good agreement. The major discrepancy between the mass flow rate data was about 21%. These results show that the mathematical modeling worked well for predicting the overall characteristics of the flow and can be generically used to other oil-refrigerant mixtures.