A STUDY OF THE FLOW OF REFRIGERANT THROUGH A CAPILLARY TUBE

Abstract

Present experimental work has been done to study the flow of refrigerant R-134a through the straight adiabatic capillary tube with different lengths and diameters. The effect of tube diameter and tube length on the mass flow rate has been studied. The mass flow rate increases with increase of the inlet sub-cooling and tube diameter and mass flow decreases with increase in inlet sub-cooling and tube length. The mass flow of the refrigerant is more sensitive to the tube diameter as compared to the other parameters i.e. when tube diameter increases, the mass flow rate of the refrigerant increases. The mass flow rate is a function of the inlet sub-cooling and inlet quality. The temperature at the end of the capillary tube is less in case of inlet quality as compared to the inlet sub-cooling. Temperature remains almost constant when refrigerant in liquid phase (single phase). The temperature at the end of the capillary tube is less in case of small tube length and larger tube diameter. As refrigerant goes into two-phase (liquid vapor mixture) the temperature of the refrigerant decreases continuously. This report presents some basic features of flow of refrigerant through capillary tube as expansion device, the details of the components of the. experimental set-up, calibration of pressure gauges and thermocouples and results of the present study