Bonded Combustor Wall for Turbine Engine Thermal Management
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Solution Overview
Problem
The existing turbine engine combustors face limitations due to the melting point and thermal erosion characteristics of nickel alloy materials, leading to performance and efficiency issues, and thermal warping causes gas leakage between the shell and heat shield, reducing engine performance.
Innovation Solution
A combustor design utilizing a partial transient liquid phase bonded connection between the heat shield and shell, with an optional intermediate element, allowing for bonding of dissimilar materials and reducing gas leakage, and incorporating a cooling cavity to manage thermal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If nickel alloy material is used for shell and heat shield, then mechanical strength is sufficient, but temperature limit is constrained by melting point and thermal erosion
Solution Approach 1:
The patent employs composite material construction where the heat shield is made from a material with higher temperature resistance than the nickel alloy shell. This composite approach allows the combustor to withstand temperatures exceeding the melting point of nickel alloy materials while maintaining structural integrity. The heat shield material is specifically selected to have superior thermal erosion characteristics, enabling operation at temperatures that would otherwise cause thermal erosion and failure of conventional nickel alloy components.
2Ease of manufacture
If shell and heat shield are mechanically fastened by threaded studs, then assembly is straightforward, but gas leakage occurs due to thermal warping
Solution Approach 1:
The patent replaces the mechanical fastening system (threaded studs) with a bonded connection system. This substitution eliminates the problems associated with mechanical fasteners under thermal conditions, specifically the thermal warping that causes gas leakage. The bonded connection provides a continuous, seamless joint between the shell and heat shield that maintains gas tightness even when thermal expansion and warping occur during engine operation.
3Reliability
If shell and heat shield are bonded, then gas leakage is reduced, but manufacturing complexity increases due to bonded connection process
Solution Approach 1:
The patent utilizes parameter changes in the bonding process, specifically employing a transient liquid phase bonding technique where the bond interface transitions through different physical states. This approach, while advanced, provides a controlled manufacturing process that achieves superior gas tightness. The bonding parameters (temperature, time, pressure) are optimized to create a strong, leak-free joint between dissimilar materials (shell and heat shield) without requiring excessively complex manufacturing infrastructure.
4Temperature
If dissimilar materials are used for shell and heat shield, then temperature resistance is improved, but bonding difficulty increases
Solution Approach 1:
The patent employs an intermediate bonding layer or interface material that facilitates the bonding between dissimilar materials (shell and heat shield). This intermediary element is specifically designed to be compatible with both materials, enabling effective bonding despite their different thermal and mechanical properties. The intermediate layer acts as a mediator that transfers and distributes thermal and mechanical stresses, allowing the dissimilar materials to be successfully joined while maintaining both temperature resistance and manufacturing feasibility.
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 solution enhances the temperature limits of the combustor, reduces gas leakage, and improves the overall efficiency and performance of the turbine engine by effectively bonding dissimilar materials and managing thermal stresses through the cooling cavity.
Implementation Method 1
The bonded connection is a partial transient liquid phase bonded connection
Implementation Method 2
A cooling cavity is defined between the shell and the heat shield
Data Source
Figure 1
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Figure 4
AI summary
A combustor wall is provided for a turbine engine. The combustor wall includes a shell, a heat shield and a combustion chamber. The heat shield is connected to the shell by a bonded connection, and defines a portion of the combustion chamber. A cooling cavity is defined between the shell and the heat shield.