Tania Bhatia

CMC Combustor Liner Demonstration in a Small Helicopter Engine

UTRC and P&W Canada partnered to demonstrate an advanced combustor configuration that was enabled by high temperature CMC materials, in a PW200 series combustor. The PW200 series have reverse-flow combustors and the program presented significant challenges in design and fabrication. The advanced CMC configuration was successfully tested in a PW206 combustor rig. At full power, a 40–50% reduction in pattern factor relative to the bill-of-material metal combustor was measured. The combustor exit plane temperatures were generally better mixed due to the combined effects of (1) eliminating the cold film layers near the combustor walls and (2) the increase in fuel injector count enabled by the increase in dilution air. The CMC combustor was also successfully tested in an engine configuration. Post test gas path surfaces of the EBC coated CMC combustor components were in good condition.Copyright

Advanced Environmental Barrier Coatings for SiC/SiC Composites

Environmental barrier coatings (EBCs) are being developed for silicon carbide fiber reinforced silicon carbide matrix (SiC/SiC) composites to protect against accelerated oxidation and subsequent silica volatilization in high temperature, high-pressure steam environments encountered in gas turbine engines. Engine testing of three-layer barium strontium aluminosilicate (BSAS) has demonstrated a life of over 15,000 hours in a combustor liner application at a nominal temperature of 2200°F (1204°C). The engine field tests have shown that useful engine life is limited by BSAS recession and potential eutectic reactions between BSAS and silica. BSAS based coatings have also been shown to survive severe thermal gradient burner rig tests with 2700°F (1482°C) surface temperature and a 300°F (167°C) gradient through the coating. Promising EBC candidates for longer life and/or higher temperature applications include strontium aluminosilicate (SAS) based coatings.Copyright

Environmental Barrier Coatings for Monolithic Silicon Nitride: Bond Coat Development

Environmental barrier coatings (EBCs) are being developed for silicon carbide (SiC) based composites and monolithic silicon nitride (Si3 N4 ) to protect against the accelerated oxidation and subsequent silica volatilization in high temperature high-pressure steam environments encountered in gas turbine engines. It has been found that the application of EBCs developed for SiC-based composites (EBCSiC ) to monolithic silicon nitride results in a loss of room temperature mechanical strength of the monolithic substrate. In this paper, we discuss the development of a bond coat system tailored for monolithic silicon nitride that helps retain the strength of the substrate. Some of the unique requirements and challenges associated with the processing of non-line-of-sight EBCs for Si3 N4 will also be discussed. Preliminary results from coating of airfoils will be presented.Copyright

Development and Evaluation of Environmental Barrier Coatings for Si-Based Ceramics

Environmental barrier coatings (EBCs) are being developed for silicon carbide (SiC) based composites and monolithic silicon nitride (Si3 N4 ) to protect against the accelerated oxidation and subsequent silica volatilization in high temperature, high-pressure steam environments encountered in gas turbine engines. While EBCs for silicon carbide (EBCSiC ) have been demonstrated in combustor liner applications, efforts are ongoing in the development of EBC systems for silicon nitride (EBCSiN ). The challenges of adapting EBCSiC to monolithic Si3 N4 are discussed in this paper. Progress in the area of EBCSiN including development and performance during field tests and tests simulating engine conditions are reviewed.Copyright