Dissimilar Engine Component Joining With TLP Thermal Protection
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Solution Overview
Problem
Combustion engines face challenges in joining dissimilar materials due to mismatches in thermal expansion coefficients and high thermal conductivity, which can lead to premature failure and inefficiency, particularly in the hot sections of turbine engines.
Innovation Solution
A method for joining engine components using transient liquid phase (TLP) or partial transient liquid phase (PTLP) bonds, combined with thermal protection structures, to minimize thermal and mechanical responses and optimize material combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a more refractory material is used to improve thermal resistance, then thermal resistance is improved, but weight increases and cost increases
Solution Approach 1:
The thermal protection system is segmented into multiple layers: a less refractory material layer exposed to hot gases and a more refractory material layer providing thermal insulation. This segmentation allows each material to be optimized for its specific function, reducing overall weight while maintaining thermal resistance.
Solution Approach 2:
Different materials are applied to different regions based on thermal exposure requirements. The less refractory material is used where thermal resistance is less critical, while the more refractory material is applied only where high thermal resistance is needed, optimizing the weight-to-performance ratio.
2Weight of moving object
If dissimilar materials are joined to reduce weight, then weight is reduced, but mismatch in coefficient of thermal expansion increases thermally induced strains
Solution Approach 1:
A metallic bond layer is introduced as an intermediary between the less refractory and more refractory materials. This bond layer mediates the different coefficients of thermal expansion, reducing thermally induced strains at the material interface while maintaining the weight benefits of dissimilar material construction.
Solution Approach 2:
The system uses a composite structure combining less refractory and more refractory materials with a metallic bond layer. This composite approach allows the system to achieve weight reduction while the metallic bond layer ensures reliability by managing thermal expansion mismatches.
3Temperature
If a more refractory material is used to provide thermal insulation, then thermal insulation is improved, but thermal conductivity remains relatively high
Solution Approach 1:
The thermal protection system is segmented into multiple layers: a less refractory material layer exposed to hot gases and a more refractory material layer providing thermal insulation. This segmentation allows each material to be optimized for its specific function, reducing overall weight while maintaining thermal resistance.
4Productivity
If dissimilar materials are physically joined to improve efficiency, then efficiency is improved, but different thermal and mechanical responses increase risk of premature failure
Solution Approach 1:
A metallic bond layer is introduced as an intermediary between the less refractory and more refractory materials. This bond layer mediates the different coefficients of thermal expansion, reducing thermally induced strains at the material interface while maintaining the weight benefits of dissimilar material construction.
Solution Approach 2:
The bonding process utilizes controlled temperature and pressure parameters to create a reliable joint between dissimilar materials. By carefully controlling these parameters, the system achieves efficient joining while minimizing the risk of premature failure due to thermal and mechanical mismatches.
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 allows for the use of dissimilar materials in combustion engines, reducing weight and cooling demands while increasing efficiency and flexibility in structural material selection, and providing robust bonds at relatively low temperatures.
Implementation Method 1
A method for joining engine components using transient liquid phase (TLP) or partial transient liquid phase (PTLP) bonds
Data Source
Figure 1
Figure 2A~2D
Figure 3A~3B
AI summary
A method for joining engine components includes positioning a first plurality of thermal protection structures across a thermal protection space between a first thermal protection surface and a second thermal protection surface. The first and second engine components are locally joined by forming a first plurality of transient liquid phase (TLP) or partial transient liquid phase (PTLP) bonds along corresponding ones of the first plurality of thermal protection structures between the first thermal protection surface and the second thermal protection surface. The second thermal protection surface is formed from a second surface material different from a first surface material of the first thermal protection surface.