Design and parametric investigation on ejector for R-744 transcritical system

A R-744 transcritical ejector for a residential air-conditioning unit was developed. The velocity of nozzle throat part in the ejector, which is the sonic velocity in two-phase CO2 fluid, was calculated with two difference models. The results from the two models were compared. In order to improve the flashing process in the throat part, the throat part pressure was analyzed and calculated according to the 'metastable' fluid character. According to the analysis above and based on energy, mass continuity and momentum equations, the pressure and velocity distribution along the nozzle were calculated. Two different models were applied in the mixing part calculation: an isobaric model and a pressure rising model. The velocity and pressure distribution from these two models were compared and discussed. The diffuser part was calculated based on energy, mass continuity and momentum equations.