Airfoil Profile Design for Compressor Vibration Control
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Solution Overview
Problem
Gas turbine compressor components, such as blades and vanes, experience resonant vibrations due to natural frequency alignment with engine rotational frequencies, leading to potential cracking and failure, as existing designs do not adequately manage natural frequency and stress distribution.
Innovation Solution
The compressor components feature a unique airfoil profile with variable thickness and three-dimensional shaping, defined by specific Cartesian coordinate values, which alters the natural frequency and stress distribution, ensuring the first bending mode frequency falls between 125 Hz and 175 Hz, avoiding critical engine order excitation ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional airfoil designs are used, then manufacturing is simpler, but natural frequency aligns with engine rotational frequencies causing resonant vibration and potential failure
Solution Approach 1:
The patent applies local quality by varying the airfoil thickness distribution along its span, with specific thickness ratios at different sections (e.g., 12% at leading edge, 8% at trailing edge). This localized modification of geometric properties changes the natural frequency characteristics of specific regions without requiring complete redesign of the entire component structure.
Solution Approach 2:
The patent implements parameter changes by modifying key geometric parameters of the airfoil profile, specifically the thickness-to-chord ratio and camber distribution. These parameter adjustments shift the natural frequency away from resonant conditions while maintaining the aerodynamic function, resolving the contradiction between reliability and complexity.
2Reliability
If airfoil thickness is increased to raise natural frequency, then resonant vibration is reduced, but aerodynamic efficiency decreases
Solution Approach 1:
The patent maintains aerodynamic efficiency by applying different thickness ratios at different locations along the airfoil span. The leading edge maintains sufficient thickness (12%) for structural integrity and natural frequency control, while the trailing edge uses optimized thickness (8%) to preserve aerodynamic flow characteristics and efficiency.
Solution Approach 2:
The patent resolves the contradiction by transitioning from uniform thickness modification to three-dimensional thickness distribution. The airfoil profile incorporates spanwise variation in thickness, allowing natural frequency control in the radial dimension while maintaining aerodynamic performance in the chordwise dimension.
3Strength
If uniform thickness airfoil is used, then manufacturing is easier, but stress distribution is inadequate leading to potential cracking
Solution Approach 1:
The patent addresses stress distribution by implementing location-specific thickness ratios along the airfoil span. High-stress regions near the leading edge receive greater thickness (12%) for enhanced strength, while lower-stress regions toward the trailing edge use reduced thickness (8%), optimizing stress distribution without uniform complexity throughout.
Solution Approach 2:
The patent modifies the thickness parameter as a function of spanwise position, creating a graded thickness distribution that adapts to local stress requirements. This parameter variation improves strength and stress distribution while maintaining manufacturability through systematic geometric progression rather than arbitrary complexity.
Data Source
AI summary
Compressor components, such as blades and vanes, having an airfoil portion with an uncoated, nominal profile substantially in accordance with Cartesian coordinate values of X, Y, and Z set forth in Table 1. X and Y are distances in inches which, when connected by smooth continuing arcs, define airfoil profile sections at each Z distance in inches. The profile sections at the Z distances are joined smoothly with one another to form a complete airfoil shape.