Gas Turbine Blade Platform Curved Corner Resonance
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Solution Overview
Problem
Gas turbine engine blade platforms experience material loss due to excitation of certain modes from unsteady-state air flow, leading to downstream damage, and complete redesign of compressor blades for existing engines is costly and time-consuming.
Innovation Solution
A redesigned gas turbine engine compressor blade with a partially curved cropped corner that avoids resonance, featuring a J-shaped or straight cropped corner, calculated using a numerical model to reduce vibratory stress and increase mode frequency beyond the operating range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complete redesign of the compressor blade is performed, then the blade platform resonance issue can be fully resolved, but the cost and time consumption increase significantly
Solution Approach 1:
The blade is divided into separate components: the existing airfoil section and a new platform section. Only the platform portion requiring modification is redesigned and manufactured separately, then attached to the existing blade. This segmentation allows resonance issues to be resolved without redesigning the entire blade assembly.
Solution Approach 2:
The problematic platform corner section is extracted and removed from the existing blade. A new, optimized platform section with modified geometry is then created and attached in its place. This extraction approach isolates the resonance problem to a specific component that can be independently redesigned.
2Reliability
If the blade platform corner is modified to avoid resonance, then material loss is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The platform corner geometry is pre-calculated and pre-designed to avoid resonance before manufacturing. The optimized platform section is manufactured in advance with the correct geometry, then attached to the blade. This preliminary design and manufacturing approach prevents material loss without requiring complex in-service modifications.
Solution Approach 2:
A new platform section is created as a separate component that can be manufactured using standard machining or additive manufacturing processes. This copied platform section replicates the optimized geometry without requiring modification of the original blade structure, simplifying the manufacturing process.
3Reliability
If the blade platform is retro-fitted with a redesigned corner, then resonance is avoided, but the retrofitting process becomes complex
Solution Approach 1:
The retrofit process segments the modification into discrete steps: removing the old platform corner, preparing the attachment surface, and attaching the new platform section. This segmentation makes the retrofit process more manageable and less complex than a complete blade redesign.
Solution Approach 2:
A separate platform section serves as an intermediary component between the existing blade and the desired resonance-free geometry. This intermediary platform section can be manufactured independently and attached to the blade, simplifying the retrofit process compared to directly modifying the original blade structure.
Data Source
AI summary
A gas turbine engine compressor blade includes an airfoil and a root section connected to a blade platform therebetween and an at least partially curved cropped corner of the blade platform. The corner shape and size may avoid resonance of blade during engine operation. The corner may be J-shaped including a straight section extending from the pressure side edge towards the suction side edge of the platform and a curved section extending from the straight section to an uncropped portion of the platform trailing edge of the platform. A method of designing the cropped corner includes choosing shapes and sizes of the cropped corner for numerically analyzing and determining shape and size for the cropped corner using a numerical model to iteratively numerically analyze aerodynamically the cropped platform with different shapes and sizes of the cropped corner. The numerical model may be validated with engine or component testing of the blade having a cropped platform with at least one of the shapes and sizes.