Cross Key Anti-Rotation Spacer for Gas Turbine Compressor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engine components experience thermal expansion and contraction during transient operations, leading to potential misalignment and rotational issues between compressor spacers and disks, causing wear and damage.
Innovation Solution
A cross key ring with alternating keys and gaps is used to prevent rotation between spacers and compressor disks by engaging with spacer teeth, providing an interference fit and securing the cross key ring to the disk via pins or integral formation, which helps maintain alignment during thermal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a retaining ring arrangement is used to hold components axially, then axial positioning is improved, but rotational stability deteriorates due to thermal expansion causing misalignment
Solution Approach 1:
The spacer is segmented into multiple discrete keys (typically three or more) distributed around its circumference, each key independently engaging with corresponding features on the disk and compressor component. This segmentation allows each key to accommodate thermal expansion independently while collectively maintaining both axial positioning and rotational stability against misalignment during temperature transients
2Stability of the object's composition
If components are tightly coupled to prevent misalignment, then alignment stability is improved, but thermal stress increases due to restricted expansion
Solution Approach 1:
The keys are designed with specific geometric characteristics including tapered surfaces and controlled clearance fits that provide localized engagement points. These keys maintain alignment stability at critical interfaces while allowing controlled movement and expansion in non-critical areas, thereby preventing excessive thermal stress buildup throughout the component assembly
3Device complexity
If a simple retaining ring is used, then device complexity is reduced, but anti-rotation capability is insufficient under thermal transients
Solution Approach 1:
The keys are designed with asymmetric geometries including tapered surfaces and non-uniform cross-sections that provide superior anti-rotation capability compared to simple cylindrical retaining rings. The asymmetric design creates mechanical interference fits that resist rotational forces while maintaining ease of assembly and relatively simple overall structure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The cross key ring effectively prevents spacer rotation relative to the disk, reducing wear and extending the life of compressor assemblies by maintaining secure alignment during startup and shutdown.
Implementation Method 1
The forward extension can receive the cross key ring in an interference fit with the forward extension inner surface, such that the ring aft face is disposed adjacent to the forward disk face
Implementation Method 2
The components may thermally expand at different rates resulting in a loss of pilot between components and thermal stresses and strains within components
Data Source
AI summary
This disclosure provides a cross key anti rotation spacer for use in a gas turbine engine. A compressor disk assembly can have a cross key ring having a plurality of keys, teeth, or castellations, alternating with a plurality of gaps to form a cross key surface. The keys or teeth of the cross key surface can mesh with corresponding teeth formed on a spacer of a compressor rotor assembly. The spacer teeth, in connection with the teeth or keys of the cross key ring can prevent rotation between the spacer and compressor disk. This is particularly beneficial during transient operations, such as startup and shutdown of the gas turbine engine.