LAPSE:2023.26485
Published Article
LAPSE:2023.26485
A Theory for Power Extraction from Passive Accelerators and Confined Flows
Robert Freda, Bradford Knight, Siddharth Pannir
April 3, 2023
No valid fluid theory exists for power extraction from unpressurized confined flow. The absence of a valid model to determine baseline uniform power extraction in confined flows creates difficulties in characterizing the coefficient of power. Currently, the primary body of research has been limited to Diffuser Augmented Wind Turbines (DAWTs) and passive fluid accelerators. Fluid power is proportional to the cube of velocity; therefore, passive acceleration is a promising path to effective renewable energy. Hypothetical models and experiments for passive accelerators yield low ideal power limits and poor performance, respectively. We show that these results derive from the misapplication of Betz’s Law and lack of a general theory for confined flow extraction. Experimental performance is due to the low efficiency of DAWTs and prior hypotheses exhibit high predictive error and continuity violations. A fluid model that accurately predicts available data and new experimental data, showing disk specific maximum CP for the confined channel at 38% of power available to disk, is presented. This is significantly lower than the 59% Betz freestream limit yielded by hypothetical models when the area ratio equals one. Experiments and their results are presented with non-DAWT accelerators, where new experimental results exceed CP limits predicted previously and correlate with the proposed predictive model.
Keywords
accelerators, Betz, climate change, freestream theory, power extraction, Renewable and Sustainable Energy, Turbines, wind power
Suggested Citation
Freda R, Knight B, Pannir S. A Theory for Power Extraction from Passive Accelerators and Confined Flows. (2023). LAPSE:2023.26485
Author Affiliations
Freda R: Design and Engineering, GenH Inc., Charlestown, MA 02129, USA
Knight B: Department of Naval Architecture and Marine Engineering, University of Michigan, Ann Arbor, MI 48109, USA
Pannir S: Design and Engineering, GenH Inc., Charlestown, MA 02129, USA [ORCID]
Journal Name
Energies
Volume
13
Issue
18
Article Number
E4854
Year
2020
Publication Date
2020-09-16
Published Version
ISSN
1996-1073
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PII: en13184854, Publication Type: Journal Article
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doi:10.3390/en13184854
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