Split Gas Turbine Case Structure for Easier Assembly and Sealing
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Solution Overview
Problem
Current static engine structures for gas turbine engines, composed of multiple tubular axial case segments, require improved manufacturing and assembly methods to enhance their design and efficiency.
Innovation Solution
A split case structure for gas turbine engines is introduced, comprising a first and second case segment that form portions of the compressor, combustor, and turbine walls, with the segments being mechanically fastened and potentially connected via intermediate bridge structures, and can be additively manufactured as a monolithic body, allowing for a more efficient assembly and reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple tubular axial case segments are used to form the static engine structure, then the structure can be assembled from discrete parts, but the assembly complexity and manufacturing difficulty increase
Solution Approach 1:
The case structure is divided into a first case segment and a second case segment that are circumferentially adjacent and attached at a joint. Each segment forms portions of both the first and second walls, allowing the structure to be manufactured as separate pieces while maintaining structural integrity. This segmentation enables easier manufacturing of individual segments while the attachment mechanism manages the complexity of assembly.
Solution Approach 2:
Each case segment is configured to form multiple functions - both the first wall and the second wall portions are integrated into single segments. The first case segment forms a first portion of the first wall and a first portion of the second wall, similarly for the second case segment. This merging reduces the total number of components needed while maintaining the segmented manufacturing approach.
2Ease of operation
If case segments are mechanically fastened together at joints, then the structure can be assembled from discrete segments, but sealing at the joints becomes more difficult
Solution Approach 1:
A seal element is positioned within a channel at the joint between the first and second case segments. The seal element acts as a flexible barrier that prevents gas flow between the segments while allowing the rigid case segments to be mechanically fastened together. This flexible sealing mechanism maintains reliability while enabling easy assembly of discrete segments.
3Adaptability or versatility
If the case structure is designed to accommodate larger rotor diameters, then the engine performance improves, but the case structure dimensions and material requirements increase
Solution Approach 1:
The case structure is segmented into circumferentially adjacent segments that can be manufactured separately and assembled together. This segmentation allows the case to be designed with optimized local thickness and material distribution to accommodate larger rotor diameters without uniformly increasing the weight of the entire case structure. Each segment can be tailored to the specific structural requirements at its location.
Data Source
AI summary
An assembly is provided for a gas turbine engine. This gas turbine engine assembly includes a split case structure. The split case structure includes a first wall, a second wall, a first case segment and a second case segment. The first wall extends axially along and circumferentially about an axial centerline. The second wall extends axially along and circumferentially about the axial centerline. The second wall is radially outboard of and axially overlaps the first wall. The first case segment is configured to form a first portion of the first wall and a first portion of the second wall. The second case segment is configured to form a second portion of the first wall and a second portion of the second wall. The second case segment is circumferentially adjacent and attached to the first case segment at a joint.