Description: Environmental barrier coatings (EBC) prevent oxidation of ceramic materials in reactive, high temperature environments such as the exhaust regions of gas turbine engines. CFDRC proposes to develop a physics based model of an EBC system interacting with the flow environment to provide better understanding of the dynamic processes that effect EBC durability under propulsion conditions. The model uses computational fluid dynamics to establish the conditions and species concentrations across the surface of the structure. The response within the coating to the environments is predicted using microscale simulations where each component of the composite coating system is discretely resolved. The micromechanics models are based on peridynamics, a mesh free theory of continuum mechanics that simultaneously solves for thermal, mechanical and concentration gradients coupled with damage to the material. Results of numerous microscale simulations are used to inform a time, temperature and stress based damage criteria for a homogenized coating material which in turn can be used to predict the extent of coating break down and mass loss at each integration point within boundary of a CFD simulation.

Benefits: The final product developed during Phase II will be a computational toolkit to model damage profiles in EBCs. The software modules will be linked to the CFD and FEM modeling tools currently in use at NASA Glenn Research Center, directly interfacing with their current turbine materials research programs. These modules will combine automated scripts with high-fidelity simulation programs to model and analyze EBC material behavior.

Rolls-Royce and Lockheed Martin Corporation are advising the direction and application of the Phase II project. CFDRC will develop the modules for industrial turbine problems and apply expert support based on their guidance