REGAL-ORC

Organic Rankine Cycle (ORC) power systems offer a great potential for waste heat recovery and environmental-friendly power generation but relatively little is known regarding the impact of real-gas effects on loss mechanisms in ORC turbine expanders. A further increase of ORC turbine efficiencies can only be achieved if relevant non-ideal compressible fluid dynamical phenomenal are better understood and modelled. Computational fluid dynamics (CFD) tools currently used in ORC design, based on Reynolds-averaged Navier-Stokes (RANS) models, are affected by many notorious flaws and uncertainties, and large-eddy-simulation (LES) or direct-numerical-simulation (DNS) methods are a promising tool for improving our fundamental understanding of these flows. The application of LES and DNS methods for real-gas flows in turbomachinery configurations is an open challenge, due to the high Reynolds numbers and the complex thermophysical models required and requires high-quality experimental data for their validation that are not available so far.