Gas Turbine Blade Variable Density Airfoil
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Solution Overview
Problem
Conventional gas turbine engine blades have a uniform density distribution along their radial direction, which can lead to inefficient material usage and structural integrity issues, particularly at the tip where higher stresses occur.
Innovation Solution
The design incorporates a variable density airfoil with a first portion near the base and a second portion near the tip, where the second portion has a lower density and an increasing true chord length, made from different materials metallurgically bonded together, optimizing material distribution and reducing pull forces at the tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform density distribution is used along the radial direction, then manufacturing simplicity is maintained, but material usage efficiency deteriorates and structural integrity issues occur at the tip
Solution Approach 1:
The blade airfoil is divided into multiple regions along the radial direction, each with different material densities. The root region uses higher density material for structural strength, while the tip region uses lower density material to reduce excessive mass and material usage. This local differentiation of material properties optimizes both structural integrity and material efficiency.
Solution Approach 2:
The blade structure is segmented into distinct zones along the radial span, with each zone assigned appropriate material characteristics. The transition from high-density root material to low-density tip material creates optimized mass distribution, reducing pull forces at the tip while maintaining overall blade strength.
2Ease of manufacture
If uniform density distribution is used along the radial direction, then manufacturing simplicity is maintained, but structural integrity at the tip deteriorates
Solution Approach 1:
Different material densities are assigned to different radial regions of the blade. The root region maintains higher density for structural strength and attachment integrity, while the tip region uses lower density material to reduce excessive mass that causes pull forces. This localized material optimization ensures structural integrity throughout the blade span.
Solution Approach 2:
The material density parameter is varied continuously or in steps along the radial direction of the blade. By changing the density parameter from high at the root to low at the tip, the design optimizes structural integrity while managing mass distribution and reducing tip pull forces.
3Reliability
If more material is used at the tip to reduce pull forces, then structural integrity improves, but overall blade weight increases
Solution Approach 1:
Instead of uniformly increasing material throughout the blade, the invention applies higher density material specifically at the root region where structural strength is most needed for attachment and load transfer. The tip region uses lower density material, achieving structural integrity through optimized local material properties rather than overall mass increase.
Solution Approach 2:
The blade employs composite material construction with different density materials in different regions. This allows the tip to have reduced density for weight savings while the root maintains high density for structural strength, creating a composite structure that optimizes both weight and integrity.
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 design enhances the structural integrity and efficiency of gas turbine engine blades by allowing more material to be used at the tip without adding to the base, improving performance and reducing material requirements.
Implementation Method 1
The first and second portions are metallurgically bonded to each other in a boundary zone and have a mixture of the first material and the second material
Data Source
AI summary
A blade for a gas turbine engine includes a body that includes an airfoil that extends in a radial direction from a 0% span position near an airfoil base to a 100% span position at an airfoil tip. The airfoil has a leading edge and a trailing edge that define the true chord length. The airfoil includes a first portion near the airfoil base with a first density and a second portion near the airfoil tip with a second density. The second density is less than the first density. The second portion includes an increasing true chord length in the radial direction. The second portion is in the range of 90% span to 100% span.