Analysis on performance characteristics of ejector with variable area-ratio for multi-evaporator refrigeration system based on experimental data

This paper presents a study on experiment and analysis of variable area-ratio ejector used in a multi-evaporator refrigeration system (MERS). The experimental rig and method are described, and the entrainment and pressure recovery performances of the variable ejector are measured at various operating and geometric conditions. The critical area ratio is proposed as an indicator of pressure recovery status; area ratios smaller than the critical ones are required to make sure that the system operates at energy saving mode. The investigation results indicate that the entrainment ratio, pressure recovery ratio and critical area ratio are strongly affected by the primary pressure and secondary pressure. Greater entrainment ratio can be obtained by increasing the secondary pressure or decreasing primary pressure. The opposite trends are found for pressure recovery ratio. Moreover, the critical area ratio varies greatly with the operation condition, and can be predicted by a linear fitting function of primary pressure or a power function in terms of secondary pressure.