Type of Document Master's Thesis Author Song, Keun Min Author's Email Address firstname.lastname@example.org URN etd-01302012-154202 Title Wall Modeled Large-Eddy Simulations in Rotating Systems for Applications to Turbine Blade Internal Cooling Degree Master of Science Department Mechanical Engineering Advisory Committee
Advisor Name Title Tafti, Danesh K. Committee Chair Ekkad, Srinath V. Committee Member Paul, Mark R. Committee Member Keywords
- Heat transfer
- Large Eddy Simulation
- Turbine blade internal cooling
- Wall layer modeling
Date of Defense 2012-01-20 Availability unrestricted AbstractLarge-Eddy Simulations (LES or wall-resolved LES, WRLES) has been used extensively in capturing the physics of anisotropic turbulent flows. However, near wall turbulent scales in the inner layer in wall bounded flows makes it unfeasible for large Reynolds numbers due to grid requirements. This study evaluates the use of a wall model for LES (WMLES) on a channel with rotation at 〖Re〗_b = 34,000 from 〖Ro〗_b = 0 to 0.38, non-staggered 90° ribbed duct with rotation at 〖Re〗_b = 20,000 from 〖Ro〗_b = 0 to 0.70, stationary 45° staggered ribbed duct at 〖Re〗_b = 49,000, and two-pass smooth duct with a U-bend at 〖Re〗_b = 25,000 for 〖Ro〗_b = 0 to 0.238 against WRLES and experimental data. In addition, for the two-pass smooth duct with a U-bend simulations, the synthetic eddy method (SEM) is used to artificially generate eddies at the inlet based on given flow characteristics.
It is presented that WMLES captures the effects of Coriolis forces and predicts mean heat transfer augmentation ratios reasonably well for all simulations. The alleviated grid resolution for these simulations indicates significant reductions in resources, specifically, by a factor of 10-20 in non-staggered 90° ribbed duct simulations. The combined effects of density ratio, Coriolis forces, with SEM for the inlet turbulence, capture the general trends in heat transfer in and after the bend.
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