Using Change Point Analysis for Image Processing of Developing Adiabatic Two-Phase Flow After Expansion Valve

This paper presents a method of analyzing images obtained from a high speed camera in a study of developing two-phase refrigerant flow after an expansion valve, using a technique known as Change Point Analysis. Specifically, a method for automating the determination of separation distance and the location of the liquid/vapor interface in stratified type flows is outlined. The experiments were conducted in transparent PVC tubes, with inner diameters of 8.7mm and 15.3mm. A working fluid of oil free R134a was used. Dynamic flow parameters of inlet quality and mass flux were varied from 5–35% and 15–40g/s, respectively. Flow visualization was achieved through the use of a high speed camera.