ejector efficiency, determination methodologies, optimum operation
The ejector efficiencies affect the ejector expansion systems significantly. This paper provides a literature review on ejector efficiency in various ejector systems, such as refrigeration and heat pump systems (transcritical systems and subcritical systems), solar systems, and steam systems. The definitions of ejector efficiency and ejector component efficiencies in literature are summarized. The assumed constant ejector component efficiencies used in ejector modeling, and the empirical correlations of ejector efficiencies derived based on measured data are summarized and compared; the methods of determining energy efficiencies are summarized. The effects of ejector geometries, operation conditions and working fluid characteristics (single phase or two-phase, zeotropic or azeotropic) on ejector efficiencies are discussed. The prospects of ejector application in and beyond the field of refrigeration are also discussed. The potential of ejector used in the low-pressure working fluids ejector systems are discussed based on variation of ejector efficiencies. This review will be useful for the further research on ejector efficiency, optimum operation and control of ejector expansion systems.