Turbine Rotor Blade Platform Inserts for Disk Stress Reduction
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Solution Overview
Problem
Existing rotor designs for turbine engines face challenges in reducing stress on the disk due to high mass of metal blades and complex fabrication of ceramic matrix composite blades, with existing attachment systems allowing gas infiltration and complicating assembly/disassembly.
Innovation Solution
A rotor design featuring a disk with primary and secondary cavities, where blades with bulb roots are axially locked in primary cavities and platform inserts with straight plateaus and radial bulbs are locked in secondary cavities, using retaining brackets to reduce stress and facilitate assembly/disassembly, allowing for a lower shank height and reduced mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metal blades are used in the rotor, then the rotor structure is simple and easy to manufacture, but the mass of the rotor increases and stresses on the disk increase
Solution Approach 1:
The patent uses ceramic matrix composite (CMC) materials for blade platforms and inserts, combining them with metal blades. This composite approach reduces the overall mass and stresses on the disk while maintaining structural integrity and ease of manufacture through standardized attachment systems.
2Weight of moving object
If ceramic matrix composite blades are used to reduce mass, then the mass decreases, but the fabrication process becomes complex and less controlled
Solution Approach 1:
The blade platform is segmented into separate CMC inserts that are manufactured independently and then assembled into the rotor. This segmentation allows for controlled fabrication of individual inserts using simpler processes while achieving the mass reduction benefits of CMC materials in the complete rotor assembly.
3Ease of manufacture
If platform inserts are assembled separately on the disk to facilitate fabrication, then the fabrication process is simplified, but gas infiltration occurs between platforms and disk deteriorating the disk
Solution Approach 1:
Retention brackets are introduced as intermediary components between the platform inserts and the disk. These brackets create a sealed interface that prevents gas infiltration while maintaining the simplified fabrication advantages of separate platform assembly. The brackets act as mediators that resolve the conflict between ease of manufacture and disk protection.
4Stress or pressure
If retaining brackets are added to the platform inserts, then stresses on the disk are reduced and assembly/disassembly is facilitated, but the device complexity increases
Solution Approach 1:
The retention brackets serve multiple functions simultaneously: they reduce stresses on the disk, facilitate assembly and disassembly operations, and prevent gas infiltration. This multi-functionality justifies the additional structural elements by providing several benefits from a single component addition.
Data Source
AI summary
A rotor for a turbine engine includes a disk having cavities called primary cavities at its periphery; a plurality of blades each having a root of which the lower part is composed of a bulb locked axially in the primary cavities; a plurality of added platforms, each being arranged between two consecutive blades, wherein the platforms have: a substantially straight plate and a bulb extending radially under the plate, the bulb being locked axially in the secondary cavities arranged at the periphery of the disk, the secondary cavities being positioned between two consecutive primary cavities; a spoiler extending in the axial direction, the spoiler forming an annular sector facing at least two consecutive blades.