Research Specifications

In this paper, the effects of Thermal Barrier Coating (TBC) thickness on temperature and stress distribution over the blade body are investigated. TBC acts like an insulation layer that increases the temperature gradient between the hot gases and the blade body. For this purpose, a 3D model of the blade body and TBC is created. Material of the substrate is considered as temperature-dependent Elastoplastic material, which its plasticity behavior is extracted point by point from the stress-strain curve. TBC is modeled as an elastic body, and the boundary conditions are applied as heat transfer coefficient. The significant point is that while the TBC thickness increases, the substrate thickness decreases respectively so that the total geometry of the whole blade remains constant in order to keep its aerodynamic behavior unchanged. Results show that increasing TBC thickness, affects significantly on the temperature distribution of the blade as some regions its surface experience a 100 °C collapse in temperature by increasing TBC thickness from 100 to 500 μm. In addition, the temperature of coolant which emerges from the top of the blade, is affected by TBC thickness, especially in the microholes near the leading and the trailing edges. Using stress evaluation, the critical region near the blade surface, which can be considered as an eligible point for crack nucleation, can be investigated. Results show that increasing TBC thickness from 100 to 500 μm, leads to 40 times decrease in the equivalent plastic strain.