Large-Eddy Simulations of Heat Transfer in a Ribbed Channel for Internal Cooling of Turbine Blades

摘要

Large-Eddy Simulations (LES) are performed in a ribbed square channel with rib height to hydraulic diameter ratio of 0.1, and rib pitch to rib height ratio of 10. The calculations are performed for a nominal bulk Reynolds number of 20,000. Hydrodynamic and thermal fully-developed conditions are assumed. Results from two mesh resolutions, 96~3 and 128~3 are presented and compared to available data in the literature. Time evolution, mean, and turbulent quantities are presented, together with the heat transfer. Both calculations capture the mean flow structures with precision and compare well with experimental data. Turbulent rms quantities also agree extremely well with available measurements. The finer mesh resolves the separated shear layer with greater precision and differences of 10-15% are observed between the two calculations. Similar differences are observed in the predictions of friction factors and Nusselt numbers between the two meshes. The friction factor and Nusselt number are underpredicted when compared to measurements in the literature.