Blade Outer Air Seal Trip Strips for Cooling Turbulence
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Solution Overview
Problem
Existing gas turbine engine cooling systems face inefficiencies in heat transfer and airflow distribution, leading to localized regions of stagnated flow and recirculation within cooling channels, which can reduce the effectiveness of thermal management.
Innovation Solution
The implementation of chevron-shaped and single skewed line trip strips within the cooling channels to generate turbulence and direct airflow, minimizing stagnation regions and enhancing convective heat transfer, combined with circumferentially extending barriers to optimize airflow distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling channels are used in blade outer air seal segments, then cooling effectiveness is improved, but localized stagnation regions and recirculation zones are created that reduce heat transfer efficiency
Solution Approach 1:
The patent introduces trip strips with specific geometric parameters (height, angle, spacing) into the cooling channels to modify flow parameters. These strips create controlled turbulence that transforms stagnant laminar flow into active turbulent flow, improving heat transfer coefficients while maintaining cooling effectiveness.
Solution Approach 2:
The patent converts the harmful stagnation and recirculation zones into beneficial turbulent mixing regions. By strategically placing trip strips at specific locations within the cooling channels, the previously harmful recirculation patterns are transformed into productive turbulent flow that enhances convective heat transfer from the blade outer air seal surfaces.
2Reliability
If trip strips are added to cooling channels to generate turbulence, then heat transfer coefficients are improved, but device complexity increases
Solution Approach 1:
The cooling channels are segmented into multiple sections with trip strips placed at specific locations within each segment. This segmentation allows turbulence to be generated only where needed rather than throughout the entire channel, reducing overall structural complexity while achieving the desired heat transfer enhancement in critical regions.
Solution Approach 2:
Trip strips are placed locally at specific positions within the cooling channels rather than uniformly throughout. The strips are positioned to address localized stagnation regions and recirculation zones, providing heat transfer enhancement only where required while maintaining simpler channel structures in other areas.
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 configuration improves heat transfer coefficients and ensures uniform airflow distribution across the cooling channels, reducing stagnation regions and enhancing thermal management within the gas turbine engine components.
Implementation Method 1
trip strips in said plurality of cooling channels for causing turbulence in said cooling airflow within the plurality of cooling channels
Implementation Method 2
a plurality of chevron-shaped trip strips having a first leg and a second leg joined together at an apex and arranged adjacent said plurality of inlet apertures, configured to direct said cooling airflow across an entire width of said plurality of cooling channels
Implementation Method 3
Cooling air may be fed into the passageways from the outboard OD side of the BOAS (e.g., via one or more inlet ports). The cooling air may exit through the outlet ports.
Data Source
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AI summary
A blade outer air seal segment assembly includes a blade outer air seal segment (50) configured to connect with an adjacent blade outer air seal segment to form part of a rotor shroud. A cooling channel (60; 60a; 60b; 60c) is disposed in the first turbine blade outer air seal segment. The cooling channel extends at least partially between a first circumferential end portion (64) and a second circumferential end portion. At least one inlet aperture (56; 56a; 56b; 56c) provides a cooling airflow to the cooling channel. A series of trip strips (72) in the cooling channel cause turbulence in the cooling airflow. The trip strips include at least one chevron-shaped trip strip (72) having a first and second leg joined at an apex arranged adjacent the inlet aperture. The trip strips also include at least one trip strip (72) having a single skewed line.