Ceramic Matrix Composite Turbine Shroud Assembly via Segmented Pre-Assembly
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Solution Overview
Problem
The assembly of turbine shroud rings with ceramic matrix composite components is challenging due to dissimilar material thermal expansion, leading to gaps and inefficiencies in gas turbine engines.
Innovation Solution
A method involving the arrangement and chocking of ceramic matrix composite shroud segments with forward and aft hooks that engage case hangers, allowing for the formation of a full ring outside the turbine case before insertion, which eliminates gaps and ensures secure engagement with the case hangers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic matrix composite components are used in turbine shrouds, then high temperature resistance is improved, but assembly difficulty increases due to dissimilar material thermal expansion
Solution Approach 1:
The turbine shroud is divided into multiple segments that can be assembled separately and then joined together. Each segment contains ceramic matrix composite components that can be manufactured and pre-assembled independently, reducing the complexity of assembling the entire shroud at once and managing thermal expansion differences between dissimilar materials.
Solution Approach 2:
Transition components are introduced as intermediaries between ceramic matrix composite components and metallic components. These transition components accommodate the different thermal expansion characteristics of the dissimilar materials, enabling successful assembly while maintaining the high temperature resistance benefits of the ceramic materials.
2Ease of operation
If shroud segments are assembled inside the turbine case, then engagement with case hangers is simplified, but available assembly space is insufficient
Solution Approach 1:
Shroud segments are pre-assembled with their hooks and engagement features outside the turbine case, where there is sufficient space to perform the assembly operations. The pre-assembled segments are then installed as complete units into the turbine case, eliminating the need to perform complex assembly operations in the confined internal space.
Solution Approach 2:
The assembly process is moved from the internal dimension (inside the turbine case) to the external dimension (outside the turbine case). By assembling segments externally where space is not constrained, and then installing the complete segments into the case, the patent overcomes the space limitation without compromising engagement simplicity.
3Strength
If gaps between shroud segments are eliminated through chocking, then structural integrity is improved, but assembly complexity increases
Solution Approach 1:
The chocking features are integrated into the shroud segment design itself, merging the gap elimination function with the segment structure. The chocking features are incorporated during segment manufacturing, so that when segments are assembled together, the gaps are automatically eliminated without requiring separate chocking operations, thus maintaining structural integrity while minimizing additional assembly complexity.
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
This method effectively reduces gaps between shroud segments and maintains secure assembly, even under high temperature conditions, enhancing the structural integrity and efficiency of gas turbine engines.
Implementation Method 1
Assembly of such components present challenges because of dissimilar material thermal expansion
Data Source
AI summary
Turbine shroud structures and a method of assembling a turbine shroud into a turbine are disclosed. The method includes arranging turbine shroud segments into a full ring and inserting the full ring into a turbine case as a single unit.