Gas Turbine Rotor Blade Removable Platform Friction Fit
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Solution Overview
Problem
Gas turbine engine rotor blades experience thermal strain and oxidation due to temperature gradients between the airfoil and platform, leading to premature wear and increased maintenance costs, as the platform is formed integrally with the shank and airfoil, making it difficult to uniformly cool and replace damaged components.
Innovation Solution
A rotor blade assembly with a removable platform coupled via a friction fit, allowing for separate fabrication and replacement, enabling uniform cooling and reducing thermal stresses by allowing the platform to expand and contract freely, and facilitating the use of less costly or lighter materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the platform is formed integrally with the airfoil and shank, then structural strength and rigidity are improved, but thermal stresses and oxidation damage increase due to temperature gradients
Solution Approach 1:
The rotor blade is divided into separate components: the airfoil and shank are formed as one integral unit, while the platform is a separate removable component. This segmentation allows the platform to be thermally isolated from the high-temperature airfoil region, reducing thermal stress and oxidation damage while maintaining structural integrity through controlled joining methods.
2Temperature
If cooling passages are introduced to cool the platform, then temperature control is improved, but thermal gradients and compressed stresses are introduced into the platform
Solution Approach 1:
The cooling function is extracted from the integral platform structure and implemented through separate cooling air supply systems that cool the platform externally or through dedicated cooling channels in the shank and airfoil that do not penetrate the platform itself. This approach controls platform temperature without introducing harmful thermal gradients and compressed stresses within the platform material.
3Manufacturing precision
If the platform is made accessible for cooling to all regions, then uniform cooling is improved, but device complexity increases
Solution Approach 1:
The cooling system is designed with universal cooling air supply pathways that serve multiple regions of the platform through a unified cooling architecture. The shank and airfoil cooling passages are configured to distribute cooling air uniformly across the platform region without requiring separate complex cooling systems for each platform location, thereby achieving uniform cooling while minimizing device complexity.
4Ease of manufacture
If the platform is formed as a single unit with the airfoil and shank, then manufacturing simplicity is improved, but maintenance costs increase when platform damage occurs
Solution Approach 1:
The platform is segmented as a separate removable component from the airfoil-shank assembly. This allows the platform to be manufactured separately using optimized processes and enables selective replacement of only the damaged platform component during maintenance, rather than requiring replacement of the entire rotor blade assembly, thereby reducing maintenance costs while maintaining manufacturing efficiency.
5Reliability
If cooling air is directed to all platform regions, then cooling effectiveness is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The cooling system employs universal cooling air distribution pathways integrated into the shank and airfoil structures that simultaneously serve multiple platform regions. This unified cooling architecture achieves effective cooling across all platform areas without requiring separate complex cooling passages for each region, thereby maintaining cooling effectiveness while minimizing device complexity and manufacturing difficulty.
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
The solution reduces platform stresses, extends the lifespan of rotor blades, decreases maintenance costs, and allows for the use of materials with improved temperature capabilities without compromising structural integrity, while enabling cored platform cooling options.
Implementation Method 1
coupling the removable platform to the rotor blade using a friction fit
Implementation Method 2
allowing the platform to expand and contract freely
Data Source
AI summary
A rotor blade assembly includes a shank, an airfoil that is formed integrally with the shank, and a removable platform coupled between said shank and said airfoil via a friction fit. A method of assembling a gas turbine engine rotor blade assembly that includes a removable platform, and a gas turbine engine rotor assembly including the removable platform are also described herein.