Gas Turbine Wheel Platform Axial Attachment for Blade Stress Reduction
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Solution Overview
Problem
Gas turbine engines face challenges in designing turbine wheels with composite blades and metallic disks that effectively withstand heat from combustion products, particularly in maintaining secure attachment and reducing stress at the blade attachment points.
Innovation Solution
A wheel assembly design featuring a multi-piece disk with dovetail-shaped blade-receiver channels and platforms with axially extending attachment features, where the blade roots and platform attachment features overlap to block radial movement, allowing for secure coupling and reduced stress on attachment points, using ceramic matrix composite materials for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite blades are coupled with metallic disks in turbine wheels, then weight is reduced and temperature resistance is improved, but stress at attachment points increases and secure attachment becomes difficult to maintain
Solution Approach 1:
The blade root is divided into multiple attachment features distributed around the circumferential perimeter, with each feature engaging a corresponding platform feature on the disk. This segmentation distributes the attachment stress across multiple discrete points rather than concentrating it at a single location, thereby maintaining strong attachment while using lighter composite materials.
Solution Approach 2:
The blade is constructed from composite materials (such as ceramic matrix composites) that provide both weight reduction and high-temperature resistance. The composite blade is integrated with metallic disk platforms through mechanically interlocking attachment features that accommodate the anisotropic properties of composite materials while maintaining strong attachment.
2Temperature
If composite blades are coupled with metallic disks in turbine wheels, then temperature resistance is improved, but stress at attachment points increases
Solution Approach 1:
The attachment interface is segmented into multiple discrete platform features and blade attachment features arranged circumferentially. This segmentation distributes thermal and mechanical stresses across multiple localized contact points, preventing stress concentration that would occur with a single large attachment interface, thereby reducing overall attachment stress while maintaining temperature resistance.
Solution Approach 2:
The blade and disk are designed with pre-configured interlocking attachment features that establish secure mechanical engagement before thermal and mechanical loads are applied. The dovetail-shaped or interlocking geometry of these features is predetermined to distribute loads evenly, preventing stress concentration under operational thermal and mechanical conditions.
3Ease of manufacture
If traditional blade attachment methods are used, then manufacturing is simpler, but structural integrity and durability are reduced
Solution Approach 1:
The attachment system uses multiple discrete platform features and blade attachment features that can be manufactured independently and then assembled. Each feature is a simple geometric form (such as dovetail shapes or interlocking profiles) that can be produced using standard machining or molding processes, maintaining manufacturing simplicity while the multi-feature configuration collectively provides enhanced reliability.
Data Source
AI summary
A wheel assembly for a gas turbine engine includes a disk, a plurality of blades, and a plurality of platforms. The disk is configured to rotate about an axis during operation of the gas turbine engine. The blades each include a circumferentially extending attachment feature that is received in the disk. The platforms each have an axially extending attachment feature that is received in the disk.