An improved thermodynamic model for supersonic real-gas ejectors using the compound-choking theory

Thermodynamic models constitute one of the essential tools to properly design supersonic ejectors. However, by their simplistic nature, most of said models remain unable to properly integrate the adequate physics that takes place within the device. Most notably, the Fabri-choking theory constitutes the building block of the large majority of those models. However, it has recently been shown that the so-called compound-choking theory may be better suited to predict the behavior of a double choked ejector. In the present study, a new state-of-the-art thermodynamic model based on the compound-choking theory is presented. First, the algorithm of the on- and off-design model is laid out. Then, the link between Fabri- and compound-choking is clarified by comparing the model with its Fabri-choking counterpart. Characteristic curves are calibrated onto air and R134a experimental data. Finally, an analytical study is performed to show that imposing the compound-choking is actually equivalent to maximizing the mass flow rate within the ejector. © 2021 Elsevier Ltd