CFD-based shape optimisation of two-phase ejector for R744.

In this study, a CFD-based shape optimisation of a two-phase R744 ejector was performed. The investigated device is to be installed in a refrigeration system of supermarkets located in two different ambient conditions. To simulate the carbon dioxide flow through the ejector, an appropriate CFD tool was developed. The applied mathematical model was based on the HEM approach. The CFD tool was controlled with the inhouse script to automatically setup the model, run the computations and post-process the obtained results. This tool was combined with the optimisation procedure for refinement of the selected parts of the ejector geometry. The objective function was formulated to maximise the total ejector efficiency. Each ejector shape was computed for two operating regimes. The optimisation results showed the increase of the ejector performance comparing to the basic geometry. However, not for all the operating regimes the ejector performance improvement was obtained.