The effects of ejector geometry parameter and refrigerant charge amount on an ejector-expansion refrigeration system

This paper presents an experimental investigation on variations of evaporating temperature (t_e) with different configuration parameters, including the nozzle throat diameter of ejector (D_t) and the capillary tube length (L_c), in an ejector-expansion refrigeration cycle (ERC) system. In addition, effects of refrigerant charge amount (CA) have been investigated at the different D_t and L_c based on the ERC system. The results show that a reasonable matching between CA and D_t or between CA and L_c can adjust the t_e while maintaining the mass flow rate of the fluid through the evaporator within an appropriate range. Furthermore, the effects of D_t and L_c on the ejector performances at the different CA have been studied. The results show that the performances of ejector are strongly affected by these parameters. The meaningful results obtained here may serve as good guidelines for developing the ejector expansion refrigeration technologies applied in practical refrigeration systems.