Modeling of non-adiabatic capillary tube flows: A simplified approach and comprehensive experimental validation

A simplified computational model for simulating refrigerant flow through capillary tubes is proposed and validated using a dataset composed of more than 1400 experimental data points, including adiabatic flows of refrigerants CFC-12, HCFC-22, HFC-134a, HC-600a, R-404A, R-407C and R-507A, and non-adiabatic flows of refrigerants HFC-134a and HC-600a, in both concentric and lateral capillary tube–suction line heat exchanger configurations. The model is based on the mass, energy and momentum conservation equations written according to their one-dimensional differential formulation. Some simplifications were added to the model in order to improve both numerical stability and computational performance. It was found that the model predicts 91.5% of the measured refrigerant mass flow rate for adiabatic and 79.3% for non-adiabatic flows within an error band of ±10%. Also, the model solves non-adiabatic flows as fast as adiabatic ones.