Simulation of the effects of oil in capillary tubes considering a separated flow model

摘要

A numerical model has been developed to simulate the effects of the oil on the performance of capillary tubes considering a separated flow model for refrigerants R-12 and R-134a. The numerical simulation integrates the one dimensional governingequations for the fluid flow (continuity, momentum and energy), using a step by step numerical method. The presence of oil in the refrigerant modifies the properties of the mixture. The separated flow model considers the two phases to he segregated withdifferent properties and different mean velocities. This numerical model was used to illustrate several effects of the oil presence on the capillary tube design parameters and on value of the flow rates. The results show good agreement with experimentaldata.