The SST Turbulence Model with Improved Wall Treatment for Heat Transfer Predictions in Gas Turbines

Heat transfer is of key importance in many gas turbine components. Most of the CFD development in this area is focused on advanced turbulence model closures including second moment closure models, and so called Low-Reynolds (low-Re) number and two-layer turbulence models. However, in many cases CFD heat transfer predictions based on these standard models still show a large degree of uncertainty, which can be attributed to the use of the -equation as the turbulence scale equation and the associated limitations of the near wall treatment. The present paper demonstrates that an optimally formulated two-equation model in combination with advanced wall treatment can overcome many problems of previous models. The SST (Shear Stress Transport) model in combination with an automatic wall treatment and a model for transition from laminar to turbulent flow was implemented in CFX-5 and applied to different test cases. In all cases the SST model shows to be superior, as it gives more accurate predictions and is less sensitive to grid variations. NOMENCLATURE Symbols

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