In this thesis project, the focus was on conducting an experimental endeavor on the performance of a multi-vane expander, operating with compressed air and hydrogen. With the current results, the concept of generating power with the use of a cost-effective air motor by expanding pressurized hydrogen is evaluated, and qualitative and quantitative comparison is done between the performance when running the device with compressed air and hydrogen. Additionally, the study includes innovative elements such as the prediction of performance based on the speed of sound, flow velocity, rotational speed, and a novel ratio proposed by the author, inspired by turbomachinery concepts. An important aspect of this research involves the systematic adjustment of rotational speed while considering temperature and physical properties, presenting a novel approach applicable to dissimilar fluids. The investigation goes beyond building an experimental set-up and proving the concept of energy recovery from hydrogen expansion, by paving the way for introducing dimensionless ratios for a comprehensive evaluation of performance in small capacity expanders. Key numerical results include: • For Compressed Air: Achieved maximum power at 800 RPM at the alternator, reaching net mechanical power output values of 40 W. • For Hydrogen: Surpassed compressed air in power output, with optimal efficiency between 2,500 and 3,000 RPM at the alternator, reaching net mechanical power output values of 120 W. Several outcomes of the study include hydrogen's distinctive behavior, showcasing superior power output compared to compressed air, even in the face of challenges posed by leaks which probably affected predominantly hydrogen. Isentropic efficiency comparisons between the two fluids instigate further inquiries, delving into a deeper understanding of the influences of leaks, viscosity, and rotational speed on overall performance.
In questo progetto di tesi, l'obiettivo era condurre uno sforzo sperimentale sulle prestazioni di un espansore multi-pala, funzionante con aria compressa e idrogeno. Con i risultati attuali, viene valutato il concetto di generazione di energia con l'uso di un motore pneumatico economicamente vantaggioso espandendo l'idrogeno pressurizzato e viene effettuato un confronto qualitativo e quantitativo tra le prestazioni quando si utilizza il dispositivo con aria compressa e idrogeno. Inoltre, lo studio include elementi innovativi come la previsione delle prestazioni basata sulla velocità del suono, sulla velocità del flusso, sulla velocità di rotazione e su un nuovo rapporto proposto dall'autore, ispirato ai concetti delle turbomacchine. Un aspetto importante di questa ricerca riguarda la regolazione sistematica della velocità di rotazione tenendo conto della temperatura e delle proprietà fisiche, presentando un nuovo approccio applicabile a fluidi diversi. L'indagine va oltre la costruzione di un apparato sperimentale e la dimostrazione del concetto di recupero energetico dall'espansione dell'idrogeno, aprendo la strada all'introduzione di rapporti adimensionali per una valutazione completa delle prestazioni negli espansori di piccola capacità. I principali risultati numerici includono: • Per Aria Compressa: Raggiunta la potenza massima a 800 RPM all'alternatore, raggiungendo valori di potenza meccanica netta di 40 W. • Per l'idrogeno: supera l'aria compressa in potenza erogata, con efficienza ottimale tra 2.500 e 3.000 giri al minuto all'alternatore, raggiungendo valori di potenza meccanica netta di 120 W. Diversi risultati dello studio includono il comportamento distintivo dell'idrogeno, che mostra una potenza in uscita superiore rispetto all'aria compressa, anche di fronte alle sfide poste dalle perdite che probabilmente hanno interessato prevalentemente l'idrogeno. I confronti dell'efficienza isoentropica tra i due fluidi stimolano ulteriori indagini, approfondendo una comprensione più profonda delle influenze di perdite, viscosità e velocità di rotazione sulle prestazioni complessive.
Experimental investigation of the performances of a vane expander processing compressed air and hydrogen
CARDONA SALAZAR, MIGUEL
2023/2024
Abstract
In this thesis project, the focus was on conducting an experimental endeavor on the performance of a multi-vane expander, operating with compressed air and hydrogen. With the current results, the concept of generating power with the use of a cost-effective air motor by expanding pressurized hydrogen is evaluated, and qualitative and quantitative comparison is done between the performance when running the device with compressed air and hydrogen. Additionally, the study includes innovative elements such as the prediction of performance based on the speed of sound, flow velocity, rotational speed, and a novel ratio proposed by the author, inspired by turbomachinery concepts. An important aspect of this research involves the systematic adjustment of rotational speed while considering temperature and physical properties, presenting a novel approach applicable to dissimilar fluids. The investigation goes beyond building an experimental set-up and proving the concept of energy recovery from hydrogen expansion, by paving the way for introducing dimensionless ratios for a comprehensive evaluation of performance in small capacity expanders. Key numerical results include: • For Compressed Air: Achieved maximum power at 800 RPM at the alternator, reaching net mechanical power output values of 40 W. • For Hydrogen: Surpassed compressed air in power output, with optimal efficiency between 2,500 and 3,000 RPM at the alternator, reaching net mechanical power output values of 120 W. Several outcomes of the study include hydrogen's distinctive behavior, showcasing superior power output compared to compressed air, even in the face of challenges posed by leaks which probably affected predominantly hydrogen. Isentropic efficiency comparisons between the two fluids instigate further inquiries, delving into a deeper understanding of the influences of leaks, viscosity, and rotational speed on overall performance.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/215074