CMC Rotor Disk Assembly Segmented Retention
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Solution Overview
Problem
The challenge lies in manufacturing rotor disk assemblies for gas turbine engines using ceramic matrix composite (CMC) materials, where traditional methods like firtree slot arrangements and metal alloys are not effective, leading to issues with retention and stress management in oxidizing gas flow environments.
Innovation Solution
A rotor disk assembly design featuring a rotor hub with radial flanges and apertures, an airfoil with a non-linear bore, and a platform segment that engages with an airfoil pin, allowing for secure retention and stress balancing using CMC materials, which facilitates the integration of CMC airfoils and platform segments to manage centrifugal and aerodynamic forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional firtree slot arrangements and metal alloys are used for rotor disk assembly, then manufacturing and retention are simplified, but the design cannot effectively manage stresses in oxidizing gas flow environments and is not suitable for CMC materials
Solution Approach 1:
The patent employs ceramic matrix composite (CMC) materials for the rotor disk assembly components including the hub, flanges, airfoil, and platform segment. This composite material approach enables the structure to withstand high-temperature oxidizing gas flow environments while maintaining structural integrity, directly resolving the reliability issue regarding stress management in such environments.
Solution Approach 2:
The retention structure is divided into discrete segmented components: a rotor hub with radial flanges, separate platform segments with apertures, and airfoil pins. This segmentation allows each component to be optimized independently for its specific function while maintaining overall structural integrity, addressing the complexity challenge by making the system modular and manufacturable.
2Weight of moving object
If CMC materials are used for airfoil and platform segment, then weight is reduced and high-temperature resistance is improved, but traditional retention methods become ineffective
Solution Approach 1:
The patent uses CMC materials for both the airfoil and platform segment, achieving significant weight reduction compared to traditional metal alloys. The CMC material properties provide high-temperature resistance and strength-to-weight ratio, directly addressing the weight reduction goal while maintaining suitability for the oxidizing gas flow environment.
Solution Approach 2:
The airfoil pin acts as an intermediary retention mechanism that bridges the CMC airfoil and platform segment. This specialized retention component is designed to work specifically with CMC materials, providing secure attachment while accommodating the material's unique properties, thus solving the manufacturability challenge for CMC components.
3Strength
If radial flanges with multiple apertures are used for airfoil retention, then secure attachment is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The hub is segmented into radial flanges with multiple apertures, and the platform segment is segmented with corresponding apertures. This segmentation allows for distributed attachment points that provide secure airfoil retention through multiple engagement locations, achieving high attachment strength while distributing manufacturing tolerances across multiple features rather than requiring single-point precision.
Solution Approach 2:
The apertures in the radial flanges and platform segment are positioned asymmetrically relative to the airfoil root geometry. This asymmetric arrangement optimizes the attachment strength by positioning retention features where they provide maximum mechanical engagement, while the non-linear bore alignment accommodates manufacturing variations and ensures proper fit.
Data Source
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AI summary
A rotor disk assembly (64C) for a gas turbine engine (20) includes a rotor hub (68C) defined about an axis of rotation (A), the rotor hub (68C) includes a blade mount section (78C) with a first radial flange (90) having a multiple of first apertures (90A) and a second radial flange (92) with a multiple of second apertures (92A).