3D Blade Geometry Analysis for Turbine Unsteadiness Reduction
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Solution Overview
Problem
Unsteadiness effects in turbomachines, such as unsteady aerodynamics, lead to increased product development costs and reduced component life due to forced response vibrations, which existing design methods struggle to predict accurately, especially in complex flowfields like those in high-work turbines.
Innovation Solution
The use of full-surface geometric measurements and computational fluid dynamics analysis to identify and mitigate unsteadiness effects by creating a distribution of turbine blades that minimizes resonant stress, through the measurement of as-built geometries and statistical analysis to select low-unsteadiness airfoils for placement around the turbine wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If structural changes are made to move critical modes out of engine operating ranges, then resonant stresses are reduced, but performance degrades and weight increases
Solution Approach 1:
The patent changes the geometric parameters of the airfoil (camber, thickness distribution, leading edge radius) to modify the unsteady aerodynamic loading characteristics. By adjusting these parameters, the blade can withstand resonant stresses without requiring additional structural reinforcement, thus avoiding weight increase while maintaining strength.
Solution Approach 2:
The patent applies local geometric modifications to specific regions of the airfoil (such as the leading edge or trailing edge) to target the unsteady loading patterns. This localized approach allows for stress reduction in critical areas without globally increasing the structural mass of the entire blade.
2Strength
If structural changes are made to move critical modes out of engine operating ranges, then resonant stresses are reduced, but performance degrades
Solution Approach 1:
Instead of changing the operating range or adding structural mass, the patent modifies the airfoil geometric parameters to alter the unsteady aerodynamic characteristics. This allows the blade to maintain its original operating range and performance while reducing resonant stresses through optimized geometry that minimizes unsteady loading.
Solution Approach 2:
Rather than trying to avoid the resonant frequencies by changing structural properties, the patent inverts the approach by modifying the aerodynamic geometry to reduce the unsteady forcing itself. This addresses the problem at its source rather than reacting to its effects.
3Strength
If aerodynamic design attempts are made to mitigate unsteady forcing, then resonant stresses are reduced, but design complexity increases
Solution Approach 1:
The patent uses systematic variation of standard airfoil geometric parameters through established design methodologies. This approach reduces design complexity by relying on proven parameter studies and optimization techniques rather than requiring entirely new aerodynamic concepts or complex active control systems.
4Ease of manufacture
If geometric variations are not accounted for, then manufacturing is simpler, but prediction accuracy of unsteadiness deteriorates
Solution Approach 1:
The patent focuses on the most critical geometric parameters that have the greatest influence on unsteady aerodynamics (such as leading edge radius, camber distribution, or trailing edge geometry). By identifying and controlling only these key local features, the patent achieves improved prediction accuracy without requiring complete control over all manufacturing dimensions.
Data Source
AI summary
Identifying effects of geometric variations of physical parts may include measuring one or more surfaces of a physical part in three-dimensions, analyzing measurements of the physical part to determine a geometric variation from a baseline model, modifying an existing computational fluid dynamics (CFD) mesh for the baseline model based on the geometric variation using a mesh metamorphosis algorithm to create a target mesh for the physical part, and analyzing the target mesh using a CFD analysis to determine an effect (e.g., an effect on unsteadiness) in a system caused by the geometric variation.