INTERNAL TURBINE BLADE COOLING SIMULATION: ADVANCED MODELS ASSESSMENT ON RIBBED CONFIGURATIONS

Many actors of the Gas Turbine (GT) world are today concerned by environmental issues. This is why they are always willing to increase further GT efficiencies. A way to achieve this is rising the turbine entry temperature, providing that the blade turbine is sufficiently cooled to withstand it. This paper investigates a method to use CFD as a design tool, to optimize blades internal coolant channels shapes. It focuses on the use of advanced RANS models combined with a wall law approach to keep CPU costs reasonable. The numerical study relies on experimental data from the MERCI test rig, where a U-shaped coolant duct representative of internal blade turbine channels was tested. The results obtained are encouraging, some need of local mesh refinements have been identified though. The computed heat exchange distributions yield the right trends and well reproduced the effects of rotation, but to go further in the thermal assessment of the models, wall conduction effects will have to be accounted for.