Modeling of refrigerants flow through components of the refrigeration system

Abstract

This research project intends to analyze the refrigerant flow through two components commonly used in domestic refrigeration systems: the non-adiabatic capillary tubes and the wire-and-tube condensers. This analysis is part of a wider project which the main objective is to elaborate a model to simulate the behavior of the vapor compression refrigeration system starting from the combination of the individual models of each component of the system. Mathematical models will be elaborated for the numeric simulation of the flow through the components. The flow through the non-adiabatic capillary tube will be divided into a single-phase region, of subcooled liquid, and a liquid-vapor two-phase flow region. The flow through the wire-and-tube condenser will be divided into three regions: a single-phase, of superheated vapor, a liquid-vapor two-phase region and a single-phase region of subcooled liquid. At first, the homogeneous model will be employed for the two-phase flow region, that is, conditions of thermal and hydrodynamic balance will be considered among the phases. Steady state conditions will be assumed initially and afterward it will be analyzed the unsteady response of the components to the variations of the operating conditions of the system. This is the great technological interest, because in the practice steady state conditions are obtained with less frequency and the simulations models of the unsteady behavior of the system is of fundamental importance. In order to validate the developed models, the obtained results will be compared with experimental data or those results obtained by others authors available in the literature. (AU)