Gas Turbine Airfoil Trailing Edge Core Strength
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Solution Overview
Problem
The fragility of refractory metal cores used in airfoils for gas turbine engines poses a challenge in maintaining structural integrity during assembly and casting, especially in the narrow trailing edge cooling passages, which are critical for efficient heat transfer and cooling flow management.
Innovation Solution
The airfoil design incorporates pedestals in the trailing edge passage that interconnect opposing pressure and suction side walls, with a discrete tip flag passage to redirect dirt purge flow, and uses a refractory metal trailing edge core with a specific hole pattern for enhanced strength and cooling efficiency, minimizing the risk of core fracture and optimizing cooling flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refractory metal cores are used to create high density patterns of cast cooling features, then convective heat transfer is improved at low cooling flow requirements, but the cores are fragile and may break during assembly or casting
Solution Approach 1:
The core design incorporates preliminary strengthening features including reinforced walls, support structures, and optimized geometry in critical areas before the casting process. The trailing edge core portion includes strengthened regions that prevent breakage during assembly and casting operations while maintaining the high density cooling pattern configuration
Solution Approach 2:
The airfoil utilizes composite construction combining refractory metal core portions with ceramic materials. The refractory metal provides ductility and strength to prevent breakage, while the ceramic portions enable high density cooling patterns. This composite approach allows the fragile high-performance cooling features to be manufactured without core breakage
2Use of energy by moving object
If the trailing edge cooling passage is made narrow to minimize cooling flow requirements, then heat transfer efficiency is improved, but the corresponding core becomes fragile
Solution Approach 1:
The core design applies different structural qualities to different regions. The trailing edge core portion has strengthened walls and support structures in specific locations where mechanical strength is needed, while maintaining narrow passage dimensions for efficient cooling. The hole pattern density and wall thickness are locally optimized to balance structural integrity with cooling performance
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 enhances the structural integrity and cooling efficiency of the airfoil by reducing the risk of core fracture and minimizing cooling flow requirements, while maintaining effective heat transfer and aerodynamic performance.
Implementation Method 1
The passages are provided by core structures constructed from ceramic and/or refractory metal cores, which provide correspondingly shaped cooling passages within the airfoil
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An airfoil has a body that includes leading and trailing edges that adjoin pressure and suction sides to provide an exterior airfoil surface. A cooling passage extends in a radial direction from a root to a tip. A trailing edge cooling passage interconnects the cooling passage to the trailing edge. The trailing edge cooling passage includes first and second pedestals of different sizes that are arranged in a repeating pattern with respect to pedestals of the same size and with respect to pedestals of different sizes.