Numerical investigation of an Organic Rankine cycle radial inflow two-stage turbine

The Organic Rankine cycle power plants have recently been the subject of intensive and remarkable growth in research worldwide. The system operates using very impressive technology to convert low to moderate heat sources into useful electrical power by means of a turbine. It offers the advantages of better operating performance, less crowded components compared to the classical steam and gas power plants for low power ranges, and more importantly, no greenhouse gas effects on the atmosphere. Numerical investigations of the turbine play a major role in improving the performance of the system, and an accurate CFD simulation interfaced with accurate thermodynamic models is considered a significant step in the design and prediction of the turbine performance. This paper draws both numerical and experimental performance maps of an ORC radial inflow two-stage turbine, starting with experimental data collection and refinement, passing by the performance parameters calculation. A commercial CFD tool was used to study the grid-independency of the numerical performance maps; a medium and fine mesh were generated and checked against the experiments. The look-up-tables interpolation method was implemented in this study to evaluate the working fluid thermodynamic properties. The main objective of this work is the validation and improvement of the numerical model prediction with respect to the experimental results.