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Modeling and simulation of the temperature and stress fields in a 3D turbine blade coated with thermal barrier coatings

ABSTRACT

Prediction of the stress distribution on a 3D turbine blade coated with thermal barrier coatings (TBCs) plays a key role in analyzing the failure of TBCs. In this work, a 3D finite element model of turbine blade coated with multilayer-structure TBCs is developed, in which conjugate heat transfer analysis and the decoupled thermal-stress calculation method are adopted. To obtain a closer to the actual temperature field, the external flow field performed by three turbulence model (RNG k-ε, realizable k-ε and SST k-ω turbulence model) are analyzed. It is found that the temperature and pressure distribution of the flow field performed by realizable k-ε turbulence model are much closer to the experiment data. TBCs present an excellent insulating effect. The heat insulation performance at the leading and trailing edges is relatively better than the suction and pressure sides. Based on the thermal-stress simulation results, the dangerous regions of TBCs are predicted. It is shown that the maximum principal stress of ceramic layer locate at both suction and pressure surfaces near leading edge and trailing edge. Furthermore, the stress level of ceramic layer is higher than that of bond coating, TBCs may spall off at these regions, especially the ceramic layer.

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