Gas Turbine Airfoil-Platform Cooling Configuration
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Solution Overview
Problem
Conventional cooling designs for gas turbine vanes face limitations in effectively cooling both airfoil and platform regions due to constraints in investment casting processes, leading to inefficiencies in cooling air flow and increased pressure losses, which affect the thermal efficiency and reliability of turbine components.
Innovation Solution
A cooling configuration that integrates serpentine cooling passages with airfoil and platform skin cooling passages, utilizing impingement holes and baffle plates to resupply cooling fluid and maintain a favorable pressure ratio, combined with advanced manufacturing techniques like additive manufacturing to create complex cooling geometries, allowing for improved convective heat transfer and reduced cooling air requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional investment casting processes are used for cooling designs, then manufacturing simplicity is maintained, but cooling effectiveness is limited due to separation of airfoil and platform cooling circuits
Solution Approach 1:
The patent merges the airfoil cooling circuit and platform cooling circuit into a single integrated cooling system. The serpentine passage extends continuously from the airfoil through the platform, allowing cooling fluid to flow through both regions without separation. This integration improves cooling effectiveness while maintaining manufacturing feasibility through investment casting processes.
Solution Approach 2:
The cooling passage transitions from a two-dimensional planar configuration to a three-dimensional serpentine path that winds through both the airfoil and platform regions. This dimensional transition allows the cooling fluid to access both cooling zones through a continuous passage, improving overall cooling effectiveness without requiring separate circuits.
2Ease of manufacture
If separate cast cooling circuits on airfoils and machined cooling holes on platforms are used, then manufacturing processes are simplified, but pressure losses increase and thermal efficiency decreases
Solution Approach 1:
The patent combines the airfoil cooling passages and platform cooling passages into a single serpentine cooling circuit that can be manufactured as an integrated component. This eliminates the need for separate cast circuits and machined holes, reducing the number of manufacturing steps while minimizing pressure losses through continuous flow path design.
Solution Approach 2:
The serpentine cooling passages are designed and integrated into the component geometry before the final manufacturing process. This preliminary design integration ensures that the cooling fluid flow path is optimized for minimal pressure losses, and the manufacturing process (investment casting) is configured to produce the integrated cooling circuit in a single operation.
3Reliability
If significant cooling air flow is required to cool vane platforms and mateface gaps, then cooling effectiveness is improved, but fuel efficiency decreases due to cycle penalty
Solution Approach 1:
The serpentine cooling passage provides continuous cooling fluid flow from the airfoil through the platform and into the mateface gaps. This continuous flow path ensures that cooling effectiveness is maintained across all hot regions without requiring separate high-flow circuits, thereby reducing the overall cooling air requirement and minimizing the cycle penalty on fuel efficiency.
Solution Approach 2:
The cooling circuit is segmented into distinct zones (airfoil cooling region, platform cooling region, and mateface gap cooling region) within a single continuous serpentine passage. This segmentation allows optimized cooling flow distribution to each region while maintaining overall flow efficiency, reducing the total cooling air required compared to separate independent cooling systems.
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
Enhances thermal efficiency by effectively cooling platform regions and maintaining adequate pressure ratios, reducing backflow and pressure losses, thereby improving the overall performance and reliability of gas turbine vanes.
Implementation Method 1
internally cooled turbine blades
Implementation Method 2
convective heat transfer
Implementation Method 3
resupply cooling fluid and maintain a favorable pressure ratio
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
An airfoil (78) includes pressure and suction side walls that extend in a chord-wise direction between leading and trailing edge and in a radial direction to provide an exterior airfoil surface. A main-body core cooling passage (90) is arranged between the pressure and suction walls in a thickness direction and extends radially toward a platform (76b). A airfoil skin cooling passage (98) is arranged in one of the pressure and suction side walls to form a hot side wall (100) and a cold side wall (102). The hot side wall (100) defines a portion of the exterior airfoil surface and the cold side wall (102) defines a portion of the core cooling passage (90). The airfoil skin cooling passage (98) extends to a platform skin cooling passage (108) arranged in the platform (76b). The platform skin cooling passage (108) is resupplied by a backside of the platform (76b).