Angled Cooling Passages in Gas Turbine Airfoil Leading Edge
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Solution Overview
Problem
In gas turbine engines, the movement of the stagnation point along the airfoil surface due to variable vane adjustments leads to uneven heat distribution and potential ingestion of hot gases through cooling holes, reducing cooling efficiency and effectiveness.
Innovation Solution
The airfoil design incorporates a combination of first and second cooling holes with passages arranged at different angles relative to the chordwise axis, with intersecting radial projections, and including diffusers with elliptical and quadrilateral cross-sections, to enhance convective cooling and film cooling efficiency, particularly by ensuring the cooling holes are in fluid communication with an internal cavity and strategically positioned on the leading edge, pressure, and suction sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling holes are distributed on the airfoil surface to provide film cooling at a single predefined stagnation point, then film cooling is provided at that point, but adjusting variable vanes changes the stagnation point position and characteristic shape, causing uneven heat distribution and potential ingestion of hot gases through cooling holes
Solution Approach 1:
The cooling system is segmented into multiple cooling holes (first cooling holes and second cooling holes) positioned at different locations and orientations on the airfoil surface. This segmentation allows each cooling hole to serve specific zones, ensuring continuous cooling coverage as the stagnation point moves during variable vane adjustment.
Solution Approach 2:
Different cooling holes are designed with specific local characteristics - first cooling holes with first cooling passages arranged at a first angle, and second cooling holes with second cooling passages arranged at a second different angle. Each cooling hole provides optimized cooling for its specific location and orientation relative to the stagnation point, adapting to local heat distribution patterns.
2Productivity
If cooling passages are arranged at different angles with intersecting radial projections, then cooling efficiency is improved by 50-220%, but device complexity increases due to multiple cooling holes and passages
Solution Approach 1:
Multiple cooling passages (first cooling passages and second cooling passages) are merged into a coordinated system where their radial projections intersect. This merging creates overlapping cooling zones that enhance overall cooling efficiency while sharing common structural space within the airfoil, rather than adding completely separate cooling systems.
Solution Approach 2:
The cooling passages are arranged in different angular dimensions relative to the chordwise axis. First cooling passages are arranged at a first angle and second cooling passages at a second different angle, creating a multi-dimensional cooling network that improves heat dissipation coverage and efficiency by utilizing angular diversity.
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 improves cooling efficiency by up to 50-220% and ensures effective convective film cooling across a range of stagnation points, reducing heat load and preventing hot gas ingestion, thereby enhancing the overall performance and durability of gas turbine engine components.
Implementation Method 1
The airfoil design incorporates a combination of first and second cooling holes with passages arranged at different angles relative to the chordwise axis, with intersecting radial projections, and including diffusers with elliptical and quadrilateral cross-sections, to enhance convective cooling and film cooling efficiency
Implementation Method 2
to enhance convective cooling and film cooling efficiency, particularly by ensuring the cooling holes are in fluid communication with an internal cavity and strategically positioned on the leading edge, pressure, and suction sides
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
An airfoil (104) according to an exemplary aspect of the present disclosure includes, among other things, a first cooling hole (201) with a first cooling passage (202) arranged at a first angle relative to a chordwise axis (D) and a second cooling hole (211) with a second cooling passage (212) arranged at a second different angle relative to the chordwise axis (D). A radial projection of the first cooling passage (202) intersects a radial projection of the second cooling passage (212).