Blisk Fillet Surface Structure for Crack Growth Control
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Solution Overview
Problem
The precise determination of leading and trailing edges and fillet connections in blisks for gas turbines is challenging due to complex geometries and aerodynamic designs, which complicates the identification of stress points and crack growth, leading to instability and potential material damage.
Innovation Solution
A blisk design featuring a surface structure on the fillet that influences crack growth and flow, with specific formations such as elevations or depressions, to enhance the stability of the blade-pedestal connection and distribute structural and aerodynamic loads effectively, thereby preventing crack propagation into the disk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If complex three-dimensional blade geometries with aerodynamic optimizations are used, then aerodynamic performance is improved, but stress concentration and crack growth risk increase due to complex fillet regions
Solution Approach 1:
The patent applies local quality by introducing a specific surface structure (elevation or depression) at the precise location of the fillet connection between blade and pedestal. This localized geometric modification changes the stress distribution characteristics specifically at the critical fillet region without altering the overall aerodynamic blade geometry, thus maintaining aerodynamic performance while improving crack resistance
Solution Approach 2:
The patent changes the geometric parameters of the fillet region by introducing an elevation or depression with specific dimensions (height between 0.1-5mm, length between 1-10mm). This parameter modification alters the stress concentration factors at the blade-pedestal connection, reducing the likelihood of crack initiation and propagation while preserving the aerodynamic function of the blade
2Ease of manufacture
If conventional smooth fillet connections are used, then manufacturing is simpler, but stress concentration occurs leading to reduced blade-pedestal connection stability
Solution Approach 1:
The invention introduces a localized surface structure (elevation or depression) specifically at the fillet connection zone. This local geometric feature modifies the stress distribution pattern at the critical connection point between blade and pedestal, enhancing connection stability without requiring complex changes to the overall manufacturing process
Solution Approach 2:
The patent utilizes curved surface features (elevation or depression) at the fillet region to replace the conventional smooth transition. This curved geometric modification helps distribute stresses more evenly across the blade-pedestal connection, reducing stress concentration and improving connection stability while remaining compatible with standard manufacturing techniques
3Manufacturing precision
If precise identification of leading edges and trailing edges is attempted in complex geometries, then aerodynamic optimization is improved, but measurement and detection difficulty increases
Solution Approach 1:
The patent introduces a surface structure (elevation or depression) at the fillet region that creates a distinct geometric feature. This feature serves as a visible and measurable reference point that simplifies the identification and measurement of blade boundaries, including leading and trailing edges, by providing a clear geometric landmark in the complex three-dimensional geometry
Data Source
AI summary
The invention relates to a blisk segment for a gas turbine, comprising at least one first blade having an airfoil, a leading edge, a trailing edge, a blade root, a suction side and a pressure side, a pedestal, and a first fillet having a device for influencing crack growth. The robustness of the gas turbine is improved in accordance with the invention in that, at the leading edge of the first blade, at least on the first fillet, a first surface structure is arranged and interacts with the crack-influencing device for influencing crack growth and for flow influencing.