Performance of fixed geometry ejectors with a swirl motion installed in a multi-ejector module of a CO₂ refrigeration system

This paper provides a performance comparison of fixed ejectors with and without swirl flow at the inlet of the motive and suction nozzles installed in a CO₂ supermarket refrigeration system. The Coefficient of Performance (COP) of the multi-ejector-based refrigeration system is dependent on the design of this device. The literature suggests that one of the possible ejector efficiency improvements can be performed using a swirl generator at the inlet of the motive nozzle. Therefore, a swirl generator was simulated for different size CO₂ ejectors under typical operating conditions in a supermarket and for a range of rotational speeds. To compare the potential of both solutions, the device performance was numerically simulated using a validated Homogeneous Equilibrium Model (HEM) model for the same transcritical parameters. A global efficiency was presented and discussed for both fixed ejector types.