Numerical simulation of two-phase refrigerant separation in conical cyclones for vapor-compression refrigeration systems

Abstract

The study emphasizes the need for vapor-liquid separators in refrigeration systems to increase efficiency and reliability. A separator utilized ahead of the evaporator serves several purposes: by removing vapor from the mixture, it improves evaporator compactness via increasing heat exchange efficiency, lowers evaporator pressure drop, and reduces compressor work. This work gives a comprehensive computational fluid dynamics (CFD) investigation of vapor-liquid separation processes for the refrigerant R32 using five conical cyclone separator models. The study focuses on evaluating flow patterns and configurations within the separator, and its geometric properties, while changing the inlet mass flow rate and quality from 0.012 kg.s^-1 to 0.036 kg.s^-1 and 0.1 to 0.3, respectively. The results reveal that all the geometric models have a liquid separation efficiency above 99 %. In addition, it has been shown that decreasing the conic diameter can improve vapor separation by as much as 25 %. Variations in the height of the cylindrical section have little effect on the vapor separation efficiency. Also, the vapor separation efficiency increases at higher refrigerant flow rates, as indicated by the study results. Relevant to the above context, this investigation yields important knowledge on the design and optimization of refrigeration systems, especially from the perspective of the vapor-liquid separation processes.