Combustor Grommet Cooling via Alternating Through and Angled Holes
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Solution Overview
Problem
The limited cooling in certain regions of a combustor grommet leads to high temperatures and rapid oxidation, reducing the durability and lifetime of the combustor.
Innovation Solution
The grommet is configured with an alternating sequence of through holes and angled holes, which provide additional cooling by allowing air to impinge and exit through impingement and effusion holes, respectively, and are strategically placed near ribs to optimize cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional cooling design is used in combustor grommet, then manufacturing is simpler, but cooling efficiency is insufficient leading to high temperatures and rapid oxidation
Solution Approach 1:
The cooling system is segmented into two distinct hole types: through holes that penetrate completely through the grommet and angled holes that terminate within the grommet. This segmentation allows different cooling mechanisms to operate in different regions, with through holes providing primary cooling paths and angled holes providing secondary cooling and impingement effects, thereby effectively reducing grommet temperature while improving durability
Solution Approach 2:
The alternating pattern of through holes and angled holes creates local variations in cooling intensity and flow characteristics. Through holes provide direct cooling paths in certain regions while angled holes provide impingement cooling in adjacent regions. This local quality variation optimizes cooling efficiency across different areas of the grommet, preventing hot spots and oxidation
2Reliability
If alternating sequence of through holes and angled holes is implemented, then cooling efficiency is enhanced, but device complexity increases
Solution Approach 1:
The design merges two different cooling approaches (through holes and angled holes) into a single integrated alternating pattern. This combination allows the system to achieve superior cooling performance by leveraging the advantages of both hole types while maintaining a regular, predictable pattern that simplifies manufacturing and inspection processes
Solution Approach 2:
The alternating sequence of through holes and angled holes creates a periodic pattern that repeats throughout the grommet structure. This periodic arrangement provides consistent cooling performance across the entire grommet while simplifying the manufacturing process, as the repeating pattern can be easily programmed into drilling machines and quality control systems
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 effectively enhances the cooling of the grommet, improving its durability and extending its lifetime while being cost-effective by utilizing a combination of through and angled holes.
Implementation Method 1
The grommet is configured to include an alternating sequence of through holes and angled holes... allowing air to impinge and exit through impingement and effusion holes... effectively enhances the cooling of the grommet
Implementation Method 2
allowing air to impinge and exit through impingement and effusion holes... strategically placed near ribs to optimize cooling efficiency
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Aspects of the disclosure are directed to a cooling design feature for inclusion in a liner 200 of an aircraft, comprising: a plurality of angled holes 208, and at least one through hole 206 separating all combinations of any two of the angled holes 208, wherein the at least one through hole 206 is oriented at an angle that is substantially perpendicular to a surface of the liner 200, and wherein each of the plurality of angled holes 208 are non-parallel to the at least one through hole 206.