Film Cooling Channel Array with Segmented Metering Portions
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Solution Overview
Problem
Existing film cooling systems in gas turbine engines face challenges in maintaining a steady film of cooling air across surfaces, often leading to vortex formation that draws hot air towards the surface instead of away from it, and there is a need for a system that reduces cooling fluid usage while maximizing efficiency and minimizing engine fuel consumption.
Innovation Solution
A film cooling channel array with multiple metering portions and a diffusion cavity is designed, where each metering portion has a constant flow cross-sectional area and a length at least three times its diameter, diffusing cooling air laterally before exit, and the array can have varying diameters and orientations to prevent vortex formation and ensure wide coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling holes are used to provide film cooling, then cooling effect is achieved, but vortex formation occurs that draws hot air towards the surface instead of away from it
Solution Approach 1:
The cooling hole is divided into multiple metering portions (first, second, and third metering portions) with different diameters and positions. This segmentation allows independent control of flow characteristics from each portion, enabling the formation of a stable cooling film while preventing vortex formation that would occur with a single large hole.
Solution Approach 2:
Different metering portions have different diameters and are positioned at different locations within the cooling hole. The first metering portion has a larger diameter and is positioned upstream, while the second and third portions have smaller diameters and are positioned downstream. This local variation in geometry optimizes the flow characteristics at different locations to maintain film stability and prevent vortex formation.
2Reliability
If cooling fluid flow is increased to maintain steady film, then film stability improves, but cooling fluid usage increases
Solution Approach 1:
The invention changes the geometric parameters of the cooling hole by incorporating multiple metering portions with specific diameter ratios and positional arrangements. This parameter optimization allows the system to maintain film stability with reduced cooling fluid flow, as the multi-portion structure inherently provides better flow distribution and film uniformity compared to a single hole design.
3Area of stationary object
If cooling hole diameter is increased to provide wider coverage, then film width increases, but vortex formation increases and film stability decreases
Solution Approach 1:
Instead of using a single large cooling hole, the invention segments the cooling function into multiple smaller metering portions. The first metering portion provides the primary cooling flow, while the second and third portions supplement it. This segmentation achieves wide film coverage through the combined output of multiple portions while maintaining stability by preventing the vortex formation that would occur with a single large hole.
Solution Approach 2:
The invention transitions from a single-point cooling source to a distributed multi-point source by introducing multiple metering portions at different positions and orientations. This dimensional distribution of cooling outlets allows the film to spread wider across the surface while each individual portion maintains smaller, more stable flow characteristics that resist vortex formation.
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
The system effectively maintains a steady film of cooling air across the surface, reducing fluid usage and enhancing cooling efficiency by diffusing air laterally, thereby protecting engine components from high temperatures while minimizing fuel consumption.
Implementation Method 1
the diffusion cavity is configured to diffuse cooling air away from the central axis in a lateral direction before the air exits the cooling channel array
Implementation Method 2
directing a relatively cool fluid, such as compressor bleed air, against a surface of a component exposed to high temperatures in order to absorb thermal energy from the component into the cooling fluid
Implementation Method 3
providing a flow of relatively cool fluid from film cooling holes within the component in order to create a thermally insulative barrier between a surface of the component and a relatively hot fluid flow
Data Source
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AI summary
A cooling channel array for a gas turbine engine is provided. The cooling channel array is carried by a component wall having an inner surface and an outer surface and comprises at least two metering portions that communicate with a diffusion cavity.