Numerical simulation of two phase refrigerant flow through non-adiabatic capillary tubes using drift flux model

Abstract

This research presents a drift flux model to simulate steady state refrigerant flow through horizontal lateral straight capillary tube-suction line heat exchangers with refrigerant R134a as a working fluid. The geometry of capillary tube is divided into two regions: An entrance length and lateral heat exchanger length. Metastable flow phenomenon is neglected in this work. To better study of fluid behavior in non-adiabatic capillary tube, according to the refrigerant state at the entrance of heat exchanger region, three modes were studied and the fundamental equations were solved for all three modes, then the results were analyzed. The present data using a drift flux model were validated with previous numerical work with a homogeneous model with obtaining reasonable agreement. By considering the slip ratio effects in drift flux model, therefore, this model could able to predict refrigerant flow behavior more accurately than other two-phase flow models in non-adiabatic flow condition through capillary tube.