Gas Turbine Airfoil Spar Segmented Plenum Cooling
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Solution Overview
Problem
Implementing ceramic matrix composite (CMC) materials in gas turbine engine airfoils is challenging due to the need for effective cooling, particularly at the leading edge where insufficient pressure cooling air poses a problem, and existing designs struggle to efficiently segregate and direct cooling air flows to optimize temperature management.
Innovation Solution
A spar design for vane arc segments in gas turbine engines featuring ribs that segregate the plenum passage into radial or circumferential zones, with through-holes to regulate cooling air flow, and a separate cooling passage to provide impingement cooling, ensuring efficient cooling of the airfoil wall while maintaining downstream cooling air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC materials are used in airfoils to extend temperature capability and lifetime, then temperature resistance is improved, but the ability to effectively cool the leading edge deteriorates due to insufficient pressure cooling air
Solution Approach 1:
The plenum passage is segmented into multiple zones using partitions and ribs, allowing separate control of cooling air flow to different regions of the airfoil. This enables optimized cooling distribution to the leading edge while maintaining overall system reliability.
Solution Approach 2:
Different regions of the airfoil are provided with different cooling characteristics through localized plenum zones. The leading edge receives targeted cooling air flow through specific partitions, creating local quality optimization where cooling effectiveness is enhanced precisely where needed despite the inherent pressure limitations.
2Reliability
If cooling air flow is increased to improve leading edge cooling, then cooling efficiency is improved, but downstream cooling air flow is reduced
Solution Approach 1:
The plenum passage is divided into multiple zones using partitions and ribs, enabling independent flow management. This segmentation allows optimized distribution of cooling air to different regions, ensuring adequate flow to both the leading edge and downstream areas simultaneously.
Solution Approach 2:
The system changes the pressure parameters within different plenum zones to optimize cooling air distribution. By maintaining appropriate pressure differentials across partitions and ribs, the system achieves efficient cooling air flow to the leading edge while preserving sufficient downstream flow.
3Reliability
If the plenum passage is segmented into zones to optimize cooling distribution, then cooling flow management is improved, but device complexity increases
Solution Approach 1:
The partitions and ribs serve dual purposes: they segment the plenum passage for optimized cooling distribution while simultaneously providing structural support to the airfoil. This merging of cooling management functions with structural elements reduces overall device complexity despite the segmentation.
Solution Approach 2:
The ribs and partitions perform multiple functions including flow segregation, structural reinforcement, and potential integration with cooling air supply systems. This multi-functionality reduces the need for separate components, thereby managing device complexity while achieving effective cooling flow management.
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 spar design effectively segregates cooling air flows to enhance cooling efficiency at the airfoil leading edge, maintaining structural integrity and temperature management, thereby extending the lifespan and performance of CMC airfoils.
Implementation Method 1
The plenum passage is embedded in the spar wall and delivers pressurized cooling air to the airfoil wall
Implementation Method 2
the ribs segregate the plenum passage into radial zones, the ribs segregate the plenum passage into circumferential zones
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
A spar (72) for a vane arc segment (60) of a gas turbine engine includes an elongated spar leg (72b) that has a spar wall (76) that circumscribes a core passage (72c). There is a plenum passage (78) embedded in the spar wall between inner (76a) and outer portions (76b) of the spar wall. The inner portion of the spar wall is fully solid such that the plenum passage is fluidly isolated from the core passage. The outer portion of the spar wall has a plurality of cooling through-holes (80) for emitting cooling air (F) from the plenum passage.