Multi-layered Turbine Spacer Managing Thermal Expansion
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Solution Overview
Problem
Turbine engine snap assemblies face challenges with high assembly forces due to preloading for tight fits, leading to potential damage during disassembly and inefficiencies from thermal expansion, which cause air leakage and slippage.
Innovation Solution
The use of additive manufacturing, specifically laser sintering, to create spacers with multiple layers of materials having varying coefficients of thermal expansion, allowing for a single monolithic component that maintains tight snap fits across all operating conditions while reducing structural drawbacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If preloading is applied to create tight snap fits, then air leakage is minimized and part slippage is prevented, but assembly force requirements increase significantly and part damage risk during disassembly increases
Solution Approach 1:
The spacer is divided into multiple layers with different materials having different coefficients of thermal expansion. This segmentation allows each layer to contribute differently to thermal management, reducing the overall thermal expansion of the spacer assembly and thereby reducing the preload force requirements while maintaining snap fit tightness.
Solution Approach 2:
The invention uses composite materials consisting of multiple layers with different coefficients of thermal expansion. This composite structure is designed to have a lower overall coefficient of thermal expansion than conventional single-material spacers, which reduces thermal expansion effects and allows for reduced assembly forces while maintaining reliable snap fits.
2Reliability
If preloading is applied to ensure tight snap fits under thermal expansion, then air leakage is minimized, but the risk of damaging parts during disassembly increases
Solution Approach 1:
The multi-layered spacer structure segments the thermal expansion management function across different materials. This allows the spacer to maintain dimensional stability under thermal conditions, ensuring snap fit tightness while reducing the preload forces that would otherwise be required, thereby enabling safer disassembly without part damage.
Solution Approach 2:
The invention changes the physical parameters of the spacer by using materials with different coefficients of thermal expansion. This parameter change results in a spacer with lower overall thermal expansion, which maintains snap fit reliability under thermal conditions without requiring excessive preload forces that would cause damage during disassembly.
3Ease of manufacture
If conventional single-material spacers are used, then manufacturing is simpler, but thermal expansion causes air leakage and efficiency loss
Solution Approach 1:
The invention employs composite materials with multiple layers having different coefficients of thermal expansion. This composite construction is designed to minimize thermal expansion of the spacer assembly, maintaining the air seal integrity and preventing air leakage that would occur with conventional single-material spacers under thermal conditions.
Solution Approach 2:
Different layers of the spacer are assigned different material properties (different coefficients of thermal expansion) based on their specific functional requirements. This local quality approach optimizes the thermal response of the spacer assembly, ensuring air seal integrity is maintained under thermal expansion conditions while managing overall dimensional stability.
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 approach minimizes air leakage and part slippage by managing thermal expansion, reducing the need for excessive assembly force and preventing damage during disassembly, thus enhancing engine efficiency and reducing repair costs.
Implementation Method 1
materials having varying coefficients of thermal expansion, allowing for a single monolithic component that maintains tight snap fits across all operating conditions
Implementation Method 2
the additive manufacturing process is laser sintering
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A turbine engine case spacer includes an air seal and a flange. The air seal is snap fit to the flange, and each flange includes at least two distinct material layers.