Gas Turbine Airfoil Frequency Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Turbomachinery airfoils face durability issues due to vibrational stresses caused by resonant frequencies during engine operation, leading to reduced lifespan, as existing designs fail to effectively manage vibrational responses under thermal, mechanical, and environmental loads.
Innovation Solution
The design of turbomachine airfoils with specific mode frequencies (1EB, 1T, 2T) and dimensions (radial span of 2.59-2.89 inches, chord length of 1.35-1.65 inches) to minimize resonant frequencies within the operating speed range, using aluminum-based alloys with defined density and modulus of elasticity, and incorporating repair methods to restore frequencies post-damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If airfoils are designed with conventional dimensions and material properties, then manufacturing is simplified, but vibrational stresses at resonant frequencies reduce durability and lifespan
Solution Approach 1:
The patent applies parameter changes by precisely controlling airfoil dimensions (radial span 2.59-2.89 inches, chord length 1.35-1.65 inches) and material properties (aluminum-based alloy with specific density 0.103 lb/in³ and modulus of elasticity 10.4 Mpsi) to achieve target resonant frequencies (1EB: 2241 Hz, 1T: 3598 Hz, 2T: 6212 Hz). This resolves the contradiction by transforming a complex durability problem into a controlled parameter optimization problem.
Solution Approach 2:
The patent implements preliminary action by pre-designing airfoils with specific mode frequencies before operation to ensure they operate outside critical resonant ranges. The frequency specifications are built into the design phase, preventing vibrational stress issues before they occur during engine operation.
2Power
If airfoils operate at resonant frequencies, then power generation is maintained, but high vibratory stresses significantly shorten airfoil life
Solution Approach 1:
The patent applies dynamics by considering the relationship between engine operating speeds and airfoil resonant frequencies. The airfoil is designed with specific modes that remain outside the operating speed range, allowing the engine to maintain power output while avoiding the harmful resonant conditions that would reduce lifespan.
3Reliability
If airfoil dimensions are increased to reduce vibrational stress, then durability improves, but the airfoil no longer fits existing engine configurations
Solution Approach 1:
The patent uses parameter changes to achieve durability within constrained dimensions. Rather than simply increasing size, the invention optimizes the specific radial span (2.59-2.89 inches) and chord length (1.35-1.65 inches) combined with material properties to achieve the desired resonant frequencies and durability without changing the overall scale of the airfoil.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prolongs the useful life of airfoils by avoiding high vibratory stresses, ensuring the airfoils operate outside critical resonant frequencies, thereby reducing the risk of high cycle fatigue and extending their operational lifespan.
Implementation Method 1
Vibrational responses of the airfoil can provide an indication of how durable the airfoil will be during engine operation. If an airfoil operates too long at a resonant frequency during engine operation, the life of the airfoil may be significantly shortened
Data Source
AI summary
A turbomachine airfoil element includes an airfoil that has pressure and suction sides spaced apart from one another in a thickness direction and joined to one another at leading and trailing edges. The airfoil extends in a radial direction a span that is in a range of 2.59-2.89 inch (65.7-73.3 mm). A chord length extends in a chordwise direction from the leading edge to the trailing edge at 50% span and is in a range of 1.35-1.65 inch (34.4-42.0 mm). The airfoil element includes at least two of a first mode with a frequency of 2241±10% Hz, a second mode with a frequency of 3598±10% Hz and a third mode with a frequency of 6212±10% Hz.