09:15
45 mins
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Advancements in experiments on non-ideal compressible flows for ORC applications
Andrea Spinelli
Abstract: In the last decade interest is grown towards the experimental characterization of non-ideal compressible flows of high molecularly complex fluids, which typically occur in diverse ORC components and especially within turbo-expanders. This is proven by the increasing number of experimental research projects related to non-ideal compressible flows for ORC applications.
The availability of experimental data describing the behavior of such flows is indeed crucial to assess design methodologies of such components and to refine CFD design/analysis tools and the thermodynamic models employed to describe the fluid properties. A significant impact is indeed expected on the final efficiency of ORCs.
In this perspective the characterization of the thermal stability of fluids for ORC applications is also of importance, standing the cycle efficiency deterioration consequent to significant fluid decomposition.
The talk will report on past, current and future activities of the CREA Laboratory of Politecnico di Milano, which since 2007 is active in the field of non-ideal compressible-fluid dynamics of organic vapors (pure fluids and mixtures) using a combined theoretical, numerical and experimental approach, and focusing on expanding flows which are typical of ORC turbo-expanders. More recently experiments on the thermal stability of organic fluids are also started. Since 2013, the CREA laboratory hosts the ERC Consolidator Project NSHOCK on Non-classical rarefaction shock-waves in molecularly complex vapors. The experimental activity is carried out employing dedicated facilities, and, most importantly, by the development of measurement techniques to be applied in high temperature non -ideal flows of organic vapors.
This kind of experimentation entails a high level of difficulty and diverse, multidisciplinary issues concur to the complexity of the study.
Advancements achieved at the CREA Laboratory in the experimental activity on non-ideal flows for ORC applications are discussed in this lecture, together with the main issues faced during test runs. Finally, an outlook is proposed on the future experimental work which are considered of importance for the improvement of ORC power system performances.
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