BOAS Vane Ejection Ports for Localized Cooling
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Solution Overview
Problem
Gas turbine engine blade outer air seals (BOAS) experience thermal distress due to hot combustion gases, and existing cooling methods result in parasitic losses as they rely on bleed air from the compressor section, which is not efficiently directed to minimize thermal distress across the entire circumferential direction.
Innovation Solution
A vane with ejection ports connected to passages that direct coolant to impinge on exposed surfaces of BOAS, providing localized cooling, with a distribution that matches the geometry of the airfoil to concentrate coolant on high-pressure areas and minimize parasitic losses by orienting passages based on the airfoil's geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If bleed air from the compressor section is communicated to the inner plenum of the BOAS for cooling, then the BOAS are cooled along the entire circumferential direction, but parasitic losses occur due to gases being heated by the compressor section but not being combusted
Solution Approach 1:
The patent applies local quality by providing localized cooling features at specific positions on the vane platform rather than uniform cooling across the entire BOAS. The one or more localized cooling features are positioned to cool only the portions of the BOAS that are in direct communication with the high-pressure fluid from the airfoil, thereby reducing parasitic losses while maintaining effective cooling where thermal distress is most severe.
2Reliability
If the relative circumferential position of upstream vane airfoil segments and combustor fuel nozzle locations is unknown, then cooling must be provided along the entire circumferential direction, but this results in inefficient coolant distribution and increased parasitic losses
Solution Approach 1:
The patent positions localized cooling features at specific locations on the vane platform where thermal distress is most severe, rather than providing uniform cooling across the entire circumferential direction. This targeted approach ensures reliable cooling coverage at critical areas while minimizing parasitic losses from unnecessary coolant consumption in areas with lower thermal stress.
3Temperature
If coolant is directed to impinge on exposed surfaces of BOAS, then thermal distress is reduced, but coolant may be ingested into intersegment gaps causing aerodynamic mixing losses
Solution Approach 1:
The localized cooling features are positioned and configured to direct coolant flow specifically at the exposed surfaces of the BOAS that experience thermal distress from high-pressure fluid communication, while avoiding areas where coolant could be ingested into intersegment gaps. This precise localization of cooling action reduces thermal distress at critical surfaces while minimizing aerodynamic mixing losses.
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 solution reduces thermal distress and parasitic losses by efficiently directing coolant to high-temperature areas, minimizing coolant ingestion into intersegment gaps, and reducing aerodynamic mixing losses, thereby enhancing the cooling effectiveness of the BOAS.
Implementation Method 1
each of the passages configured to eject coolant in a direction that impinges an exposed surface of a blade outer air seal
Implementation Method 2
The localized cooling features positioned about a cooling plane and configured to cool a portion of the exposed surface of one or more downstream blade outer air seals
Data Source
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AI summary
A vane according to an exemplary aspect of the present disclosure includes, among other things, a platform extending from an edge face and between spaced apart lateral faces and an airfoil extending outwardly from the platform. The platform includes at least one ejection port in the edge face and at least one passage connected to the at least one ejection port.