Prediction of condensation in a two stage steam ejector for a refrigeration system

An experimental refrigeration system based on a two stage steam ejector was set up in the Thermodynamics and Heat Transfer Laboratory of our Department. The system optimization and realization has been described elsewhere [1]. The primary flow in the first stage is highly supersonic and reaches very low pressure and temperature levels at the nozzle exit. As usual in the technical literature, an ideal gas model was used in the analysis. Therefore, in order to asses the validity of this analysis, verification has to be carried out with respect to real gas behaviour. High flow speed suggests the establishment of meta-stable conditions in the ejector. In order to understand the actual working condition of our system, an extensive search was made in the literature and several models compared.