Heat Shield Axial Retention Lock for Gas Turbine Diffuser
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Solution Overview
Problem
The thermal gradients caused by heat transfer from the combustor to the diffuser case in gas turbine engines lead to stress, deformation, and degradation of engine case components, reducing their operational life.
Innovation Solution
A heat shield assembly with an annular shape and a circumferentially formed groove is used to retain a support lock, creating a seal with the engine case and minimizing convective heat transfer, while an axial retention feature prevents the heat shield from axial liberation during surge events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heat shield is installed between the combustor and diffuser case, then thermal gradients and stress on the diffuser case are reduced, but the complexity of the engine case structure increases
Solution Approach 1:
The heat shield is segmented into modular components including the shield body, support locks, and retention features that can be independently manufactured and assembled. This segmentation reduces manufacturing complexity while maintaining thermal protection effectiveness.
Solution Approach 2:
The heat shield acts as an intermediary component between the combustor and diffuser case, blocking direct thermal exposure to the diffuser case while maintaining structural integrity and seal integrity through integrated support locks and retention features.
2Reliability
If support locks with axial retention features are used to secure the heat shield, then the heat shield positioning is prevented during surge events, but the manufacturing precision requirements increase
Solution Approach 1:
The support lock features asymmetric geometric profiles with tabs and grooves designed in specific non-symmetric configurations that provide directional retention. This asymmetric design ensures proper positioning while accommodating manufacturing tolerances through complementary mating surfaces.
Solution Approach 2:
The support locks are pre-configured with axial retention features during manufacturing, and the grooves are pre-formed in the heat shield, creating a predetermined interference fit that automatically engages during assembly to prevent axial movement before surge events occur.
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 heat shield assembly reduces thermal gradients and stress on the diffuser case, thereby extending its operational life by minimizing convective heat transfer and ensuring the heat shield's secure positioning.
Implementation Method 1
The thermal loads in the diffuser case may cause thermal gradients that may stress, deform, fracture, and/or degrade portions of the diffuser case over time. A heat shield assembly may be disposed between the combustor and the diffuser case to reduce the convective heat transfer from the combustor to the diffuser case.
Data Source
AI summary
A heat shield assembly for an engine case of a gas turbine engine may include a heat shield and a support lock. The heat shield may have an annular shape and a groove formed circumferentially along an inner surface of the heat shield. The support lock may have a tab extending radially outward from a distal surface of the support lock. The groove in the heat shield may be configured to retain the tab of the support lock.