Gas Turbine Rotor Blade Root Section with Metallic Cable Coupling
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Solution Overview
Problem
The challenge in gas turbine engines is securely coupling metallic cables to composite material rotor blades, as existing methods struggle to provide a strong and reliable connection, especially in open rotor configurations where larger fans are used, and composite materials complicate the attachment process.
Innovation Solution
A rotor blade design incorporating a root section formed from a combination of composite and metallic materials, where the metallic portions are strategically positioned to provide a secure connection for metallic cables, with the longitudinal centerline extending through the metallic portions, allowing for a metal-to-metal coupling that is stronger than a metal-to-composite connection, and reducing weight and increasing the operating temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite materials are used for rotor blades to reduce weight and increase operating temperature range, then weight is reduced and temperature range is extended, but the ability to securely couple metallic cables to the root section deteriorates
Solution Approach 1:
The rotor blade root section is constructed using a composite structure combining composite material portions and metallic material portions. The composite material portions (e.g., ceramic matrix composites) reduce weight and extend temperature range, while the metallic material portions (e.g., titanium or superalloy) provide secure coupling surfaces for metallic cables. This composite approach allows simultaneous achievement of weight reduction and reliable cable attachment.
Solution Approach 2:
Different portions of the root section have different material properties tailored to local requirements. The composite material portions are positioned where weight reduction and high-temperature resistance are critical, while metallic material portions are positioned specifically where cable coupling is required. The longitudinal centerline extending through the metallic portions ensures proper load distribution and coupling reliability.
2Temperature
If composite materials are used for rotor blades, then operating temperature range is increased, but the ease of manufacturing and assembling cable connections deteriorates
Solution Approach 1:
The root section uses a composite structure with distinct composite material portions and metallic material portions. The metallic portions are specifically designed to facilitate cable attachment using conventional metal-to-metal joining techniques, while the composite portions provide high-temperature capability. This division allows the blade to operate at higher temperatures while maintaining ease of cable installation.
Solution Approach 2:
The metallic material portions are strategically positioned and shaped to provide standardized coupling surfaces, making the cable attachment process straightforward and manufacturable. The composite material portions are positioned in regions where high-temperature resistance is most beneficial, creating a division of labor that optimizes both temperature performance and manufacturing ease.
Data Source
AI summary
A rotor blade for a gas turbine engine includes an airfoil section and a root section extending along a longitudinal direction between an upstream surface and a downstream surface. The root section further extends along a radial direction between an inner surface positioned at an inner end of the root section and an outer end coupled to the airfoil section. Moreover, the root section extends along a circumferential direction between a first side surface and a second side surface. Furthermore, the root section defines a longitudinal centerline extending along the longitudinal direction and positioned equidistant from the inner surface and the outer end in the radial direction. The root section includes a first portion formed from a composite material and a second portion formed from a metallic material, with the longitudinal centerline extending through the second portion of the root section.