Article
Investigation the Effects of Choking and Combustion Products Swirling Frequency on Fractures of Gas Turbine Compressor Blades
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Abstract
Premature blade fractures occurred in four gas turbine compressors at a refinery. To assess the impact of combustion instability on blade failure, such as choking and chamber resonance issues, 3D models of the combustion chamber structure and combustion flow were examined using finite element analysis and computational fluid dynamics codes, respectively. By comparing the natural frequencies of the combustion chamber with the combustion swirl frequency, it was determined that the chamber structure was not experiencing resonance. To verify the likelihood of choking, the Mach number of the combustion product flow was analyzed. The Mach number distribution results indicated that the flow was subsonic in the transition piece area. However, due to the presence of supersonic flow conditions near the swirl vanes, the flow could become supersonic under certain critical conditions. Therefore, it is recommended that operators maintain engine operation as close to the optimal design conditions as possible to avoid choking. The simulation results indicated that the blade fractures were not a result of combustion issues.
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Published by: Engineering Journals


