Turbomachine Blade Cooling Hole Triangular Diffusion
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Solution Overview
Problem
Conventional turbomachine turbine blades experience reduced cooling efficiency due to counter-rotating vortices at the outlet section of cooling holes, leading to ingestion of hot gases and separation of the cooling air flow.
Innovation Solution
A cooling hole geometry with a central edge that gradually moves the cooling fluid away from the flow axis and counter-rotating vortices, featuring tapered guiding portions that reduce the ingestion of hot gases by directing the flow away from the vortex zone, resulting in a triangular-section diffusion portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional cylindrical cooling hole with tapered diffusion portion is used, then the cooling air can be introduced into the blade, but counter-rotating vortices form at the outlet section causing flow separation and hot gas ingestion
Solution Approach 1:
The patent applies asymmetry by introducing a central edge that is offset from the flow axis, creating an asymmetric triangular-section diffusion portion. This asymmetric geometry shifts the cooling flow away from the flow axis, positioning it outside the counter-rotating vortex zones and preventing vortex-induced flow separation and hot gas ingestion.
Solution Approach 2:
The patent transitions from a conventional cylindrical (two-dimensional radial) cooling hole to a three-dimensional triangular-section diffusion portion with a central edge offset from the flow axis. This dimensional change creates a new geometric configuration that fundamentally alters flow patterns and eliminates the formation of counter-rotating vortices at the outlet section.
2Reliability
If a shaped cooling hole with single-lobe type architecture is used to channel cold air away from vortices, then cooling efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The patent uses asymmetry with a simple triangular-section diffusion portion featuring a central edge offset from the flow axis, achieving the vortex-avoidance function of complex shaped cooling holes while maintaining geometric simplicity that facilitates manufacturing.
Solution Approach 2:
The patent changes the geometric parameters of the cooling hole by introducing a triangular-section diffusion portion with specific angular configurations and an offset central edge, achieving improved cooling efficiency through parameter optimization rather than complex structural modifications.
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 enhances cooling efficiency by protecting the cooling air flow from counter-rotating vortices, reducing hot gas ingestion, and simplifies manufacturing by eliminating the need for a lobe, achieving a nearly 20% gain in cooling efficiency compared to conventional designs.
Implementation Method 1
counter-rotating vortices that form at the outlet section of this hole
Implementation Method 2
causes the flow of cool air to separate
Implementation Method 3
the point of the central edge passing through this plane is the point furthest away from the flow axis of all the points of the third surface contained in this section
Data Source
AI summary
A turbomachine component such as a blade, includes a wall provided with at least one cooling hole having a metering portion and a tapered diffusion portion. The diffusion portion includes a central edge forming a bottom of the diffusion portion that is oblique with respect to a flow axis of the cooling hole.