||With this proposal I aim to develop an accurate and robust numerical tool for the simulation of compressible two-phase flows for Organic Rankine Cycle (ORC) applications. Recent studies have shown that the power output of ORC systems may be increased up to 30% by implementing a wet-to-dry turbine expansion, which starts in the two-phase regime and ends in the dry vapor. Advanced numerical tools are required to confirm these predictions, and to investigate more accurately these flows. To ensure an adequate level of reliability, I propose to develop a numerical tool based on the non-equilibrium Baer and Nunziato (BN)-type model. The suggested model naturally takes into account non-instantaneous mass and heat transfer. By using an adaptive strategy based on non-standard criteria to predict the local flow topology, the model will also be able to deal with the different flow topologies that occur in a wet-to-dry expansion. Finally, the effects of the finite relaxation scales will be investigated through a parametric study, and specific empirical indications for two-phase ORC systems will be delivered to the community involved in their optimization and design.
The developed simulation software will be released under an open-source policy within the SU2 simulation toolkit, a choice that will help engineers solve transient two-phase fluid dynamics problems. The ensuing availability of an adaptive diffuse interface method will also contribute to answer the need for advanced numerical methods able to effectively deal with the multiscale nature of two-phase flows.
The inter-disciplinary character of the NI2PhORC project, which blends techniques of fluid dynamics, applied mathematics, and scientific computing, represents an invaluable opportunity for me to develop a solid and comprehensive scientific background to advance my scientific career within an engineering department.