Gas Turbine Cooling Hole with Reduced Downstream Diffusion Angle
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Solution Overview
Problem
Gas turbine engine components face challenges in effectively cooling the edges due to the limitations of traditional cooling hole designs, which often result in inadequate film coverage and inefficient heat dissipation at high temperatures.
Innovation Solution
The design of a cooling hole with a metering section and a diffusion section that eliminates or reduces the downstream diffusion angle, allowing for a coaxial downstream surface, enabling better film coverage and convective cooling by positioning the centerline closer to the edge, thus enhancing cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional cooling hole design with a downstream diffusion angle is used, then the cooling air can be discharged to provide film cooling, but the film cooling coverage is inadequate and heat dissipation efficiency is reduced at the edges
Solution Approach 1:
The patent changes the geometric parameters of the cooling hole by reducing or eliminating the downstream diffusion angle. This parameter modification allows the cooling air jet to remain more collimated and directed, improving both film cooling coverage and heat dissipation efficiency at the component edges.
Solution Approach 2:
The patent applies a localized solution by specifically modifying the downstream section of the cooling hole where the diffusion angle is reduced or eliminated. This local geometric change optimizes the cooling air discharge characteristics precisely at the outlet region, enhancing film cooling performance where it is most needed at the component edges.
2Area of stationary object
If the cooling hole is extended deeper to increase cooling coverage, then more internal surface can be cooled, but the edge may be damaged
Solution Approach 1:
By changing the downstream diffusion angle parameter to zero or near-zero, the cooling hole can be extended deeper into the component without compromising edge integrity. The reduced diffusion prevents the cooling air jet from eroding or damaging the edge while maintaining adequate cooling coverage.
3Area of stationary object
If the downstream diffusion angle is reduced, then film cooling footprint increases, but the diffusion section geometry becomes more constrained
Solution Approach 1:
The patent simplifies the diffusion section geometry by reducing the downstream diffusion angle to zero or near-zero values. This parameter change actually reduces geometric complexity while simultaneously increasing the film cooling footprint, as the cooling air remains more collimated and covers a larger area without requiring complex diffusion angles.
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 film cooling coverage and convective cooling efficiency, allowing for deeper penetration of the cooling hole without damaging the edge, resulting in more effective heat dissipation and increased film cooling footprint.
Implementation Method 1
Cooling air is communicated into an internal cavity of the component and can be discharged through one or more of the cooling holes to provide a boundary layer of film cooling air at the outer skin of the component
Implementation Method 2
The diffusion section of the cooling hole includes a first side diffusion angle, a second side diffusion angle and a downstream diffusion angle at a downstream surface of the diffusion section
Implementation Method 3
allowing for better film coverage and convective cooling by positioning the centerline closer to the edge, thus enhancing cooling efficiency
Data Source
AI summary
A component for a gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, a wall having an internal surface and an outer skin, a cooling hole having an inlet extending from the internal surface and merging into a metering section, and a diffusion section downstream of the metering section that extends to an outlet located at the outer skin. The diffusion section of the cooling hole includes a first side diffusion angle, a second side diffusion angle and a downstream diffusion angle at a downstream surface of the diffusion section, the downstream diffusion angle being less than the first side diffusion angle and the second side diffusion angle.