Platformless Turbine Blade Rotor Assembly
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Solution Overview
Problem
Turbine rotor speed in gas turbine engines is limited by nickel alloy blades, which crack under increased loads due to attached platforms, and ceramic matrix composite blades do not offer significant benefits in thermal capability or platform durability.
Innovation Solution
A turbine blade rotor assembly with nickel alloy blades and ceramic matrix composite platforms secured separately to the rotor, eliminating integral platforms and using CMC for flow guides and shrouds to enhance durability and airflow guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If nickel alloy turbine blades with integral platforms are used, then the blade structure is simple and manufacturing is easier, but the platforms crack under increased loads at higher rotor speeds
Solution Approach 1:
The platform is separated from the nickel alloy blade and constructed as a distinct ceramic matrix composite component. This segmentation allows the platform to be made from material better suited for withstanding high-speed loads, eliminating the cracking issue while maintaining blade integrity.
Solution Approach 2:
The platform is constructed from ceramic matrix composite material, which provides superior durability and resistance to cracking under the high loads experienced at increased rotor speeds, compared to traditional nickel alloy materials.
2Temperature
If ceramic matrix composite blades with integral platforms are used, then high temperature capability is improved, but the construction becomes more difficult and platforms are harder to provide
Solution Approach 1:
By separating the platform from the blade, the complex task of creating integral platforms in CMC blades is avoided. The platform can be manufactured as a separate component using more feasible processes, then attached to the blade, simplifying the overall construction process.
Solution Approach 2:
An intermediate attachment structure is introduced to connect the CMC platform to the nickel alloy blade. This intermediary solution allows the platform to be provided separately while maintaining a secure connection, avoiding the difficulties of direct integral construction.
3Speed
If separate ceramic matrix composite platforms are used, then platform durability at high speeds is improved, but the device complexity increases
Solution Approach 1:
The platform and blade are merged into a functional assembly where the separate CMC platform is securely attached to the nickel alloy blade. This combining approach maintains the durability benefits of separate construction while creating an integrated assembly that functions as a unified component.
Data Source
AI summary
A turbine blade rotor assembly is disclosed for a gas turbine engine. The assembly includes a rotor having nickel alloy turbine blades secured thereto. Each of the blades includes a root and an airfoil. The roots are supported by the rotor. A ceramic matrix composite platform separate from the turbine blades is supported between each pair of the turbine blades adjacent to the airfoils. In another example, the airfoil includes a perimeter. A shroud having an aperture receives the airfoil with a single shroud substantially surrounding the airfoil at the perimeter. In one example, the turbine blade includes high and low pressure sides opposite one another that extend from a tip to a root. The airfoil is free from any protrusions extending from the high and low pressure sides on a portion of the blade axially outward from the root.