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Numerical Assessment of Eddy-Viscosity Turbulence Models of an Axial-Flow Turbine at a Low Reynolds Number

Posted on:2017-11-03Degree:M.SType:Thesis
University:Florida Atlantic UniversityCandidate:Estrada, Nick DagobertoFull Text:PDF
GTID:2452390008475317Subject:Mechanical engineering
Abstract/Summary:
The flow field behavior of axial flow turbines is of great importance, especially in modern designs that may operate at a low Reynolds number. At these low Reynolds numbers, the efficiency loss is significantly augmented compared to higher Reynolds number flows. A detailed incompressible numerical study of a single stage axial-flow turbine at a low Reynolds number is investigated with the use of multiple eddy-viscosity turbulence models. The study includes epistemic uncertainty quantification as a form of numerical error estimation. The numerical results show good qualitative and quantitative agreement with experimental data. It was found that the shear stress transport (SST) k -- o turbulence model with rotation/curvature correction and inclusion of transition modeling is most capable at predicting the mean velocity distribution, which is further enhanced when the URANS formulation is employed. However, all the cases indicate a large variation in the prediction of the root-mean-squared of the turbulent velocity fluctuations.
Keywords/Search Tags:Low reynolds, Reynolds number, Numerical, Turbulence
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