The R744 multi-ejector hybrid CFD and experimentally-based reduced-order model.

The proposed hybrid reduced-order model (HROM) of the four R744 fixed ejectors installed in the multi-ejector module is presented. The ejectors HROM was built by use of the proper orthogonal decomposition together with the radial basis function interpolation to obtain high-accuracy model for a wide range of the subcritical and transcritical operating regimes. The input data for the proposed model was the combination of the experimental data of the investigated ejectors together with the numerical results obtained by use of the ejectorPL platform. The proposed HROM of each R744 vapour fixed ejector obtained a satisfactory accuracy of the motive and the suction nozzle mass flow rates for most validated points and significantly reduced the computational time. Hence, the proposed HROM of the R744 vapour fixed ejectors was successfully implemented to the Modelica dynamic simulations of the R744 refrigeration system to evaluate the system energy performance corresponding to the real ejector performance at different operating conditions.