Trailing Edge Cooling Circuit Thermal Stress Reduction
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Solution Overview
Problem
Traditional trailing edge cooling circuits in turbomachines, which use pin banks to connect pressure and suction side walls, lead to undesired thermal stresses and reduced durability due to direct heat conduction from the pressure side to the suction side.
Innovation Solution
The implementation of a trailing edge cooling circuit with separate pressure side and suction side cooling channels, where each channel converges towards the camber axis as it extends towards the trailing edge, reducing thermal stress by isolating the channels and enhancing convective cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pin banks are used to connect pressure side and suction side walls, then structural connection is achieved, but thermal stress increases and durability decreases due to direct heat conduction
Solution Approach 1:
The cooling circuit is segmented into separate pressure side and suction side channels that do not directly connect through pins. This segmentation eliminates the thermal conduction path while maintaining structural integrity through the airfoil structure itself.
Solution Approach 2:
The pin bank component is completely removed from the design. The connection function previously performed by pins is achieved through the integrated airfoil structure and separate cooling channels, eliminating the source of thermal stress and durability issues.
2Strength
If pin banks are used to connect pressure side and suction side walls, then structural connection is achieved, but thermal stress is concentrated on the suction side wall
Solution Approach 1:
The cooling circuit is divided into separate pressure side and suction side channels. This segmentation prevents thermal conduction from the hot pressure side to the cooler suction side, thereby eliminating thermal stress concentration on the suction side wall.
Solution Approach 2:
The pin bank that caused thermal stress concentration is removed entirely. The structural connection is maintained through the airfoil structure without the intermediary pins that created the thermal stress pathway.
3Reliability
If separate pressure side and suction side cooling channels are used, then thermal stress is reduced and durability is improved, but channel convergence complexity increases
Solution Approach 1:
The separate pressure side and suction side cooling channels converge and merge into a common trailing edge region. This merging allows the channels to maintain their separation for thermal isolation while combining their cooling functions at the trailing edge, achieving both durability improvement and design efficiency.
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 design effectively reduces peak thermal stresses in the trailing edge region by spreading thermal loads across the structure and improving cooling efficiency, thereby increasing the durability and robustness of the airfoil.
Implementation Method 1
air, typically bleed air from the compressor section, is forced through internal cooling passages within the airfoil and then discharged through cooling holes at the airfoil surface to transfer heat from the hot gas path component
Data Source
AI summary
An airfoil includes a leading edge, a trailing edge, a pressure side wall, and a suction side wall. The pressure side wall and the suction side wall each extend between the leading edge and the trailing edge. A camber axis is defined halfway between the pressure side wall and the suction side wall. A cooling circuit is defined in the airfoil. The cooling circuit includes a trailing edge cooling circuit. The trailing edge cooling circuit has a pressure side channel that is disposed at least partially on a first side of the camber axis and a suction side channel that is disposed at least partially on a second side of the camber axis. The pressure side channel and the suction side channel each converge towards the trailing edge as the pressure side channel and the suction side channel extend towards the trailing edge.