Turbine Combustor Wall Non-Uniform Effusion Apertures
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Solution Overview
Problem
Turbine engine combustor walls face significant temperature differentials due to varying combustion chamber gas temperatures, leading to material fatigue, which existing designs fail to adequately address.
Innovation Solution
A combustor design featuring non-uniform distributions of impingement and effusion apertures in the support shell and heat shield, respectively, to tailor cooling air distribution based on temperature gradients, ensuring isothermal conditions and reduced fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform distribution of effusion apertures is used, then manufacturing is simple, but temperature differentials in combustor walls increase causing material fatigue
Solution Approach 1:
The patent applies local quality by varying the distribution density of effusion apertures across different regions of the heat shield. Specifically, the first region (adjacent to fuel injectors) has a higher density of apertures compared to the second region, allowing localized optimization of cooling air distribution to match the non-uniform temperature gradients in the combustion chamber. This resolves the contradiction by sacrificing uniform manufacturing for targeted thermal management that prevents wall fatigue.
Solution Approach 2:
The patent changes the parameter of aperture distribution from uniform to non-uniform, specifically varying the density of effusion apertures across different radial and axial regions. The first region adjacent to fuel injectors has higher aperture density while the second region has lower density, creating a gradient that optimizes cooling air flow to where it is most needed, thereby reducing temperature differentials and preventing material fatigue.
2Reliability
If non-uniform distribution of effusion apertures is implemented, then temperature differentials are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent implements local quality by creating distinct aperture density zones: a first region with higher effusion aperture density adjacent to fuel injectors, and a second region with lower density. This localized variation in aperture distribution allows the heat shield to deliver optimized cooling air flow to high-temperature zones while reducing cooling in lower-temperature areas, thereby minimizing temperature differentials and improving thermal uniformity across the combustor wall.
Solution Approach 2:
The heat shield is segmented into multiple regions with different aperture densities. The first region (adjacent to fuel injectors) is distinguished from the second region by having a higher concentration of effusion apertures. This segmentation allows independent optimization of cooling characteristics in different zones, achieving better overall temperature uniformity while maintaining a relatively simple overall structure that does not require complex active control systems.
3Device complexity
If cooling air is uniformly distributed, then system design is simple, but hot regions receive insufficient cooling leading to high temperature differentials
Solution Approach 1:
The patent applies local quality by configuring the effusion aperture distribution to match the local thermal requirements of different combustor regions. The first region adjacent to fuel injectors, which experiences highest temperatures, is equipped with higher aperture density to receive proportionally more cooling air. The second region with lower thermal loads receives correspondingly less cooling air. This localized optimization of cooling air distribution effectively reduces temperature differentials without requiring complex active control systems or variable geometry components.
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 tailored aperture distribution significantly reduces temperature differentials within the combustor walls, enhancing cooling air distribution and minimizing material fatigue by providing more cooling air to hot regions and less to cool regions.
Implementation Method 1
The support shell can include a plurality of impingement apertures, which directs cooling air from a plenum surrounding the combustor into the impingement cavity and against an impingement cavity surface of the heat shield.
Implementation Method 2
The heat shield can include a plurality of effusion apertures, which directs the cooling air from the impingement cavity into the combustion chamber for film cooling a combustion chamber surface of the heat shield.
Data Source
Figure 1
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AI summary
A turbine engine combustor wall includes support shell and a heat shield. The support shell includes shell quench apertures, first impingement apertures, and second impingement apertures. The combustor heat shield includes shield quench apertures fluidly coupled with the shell quench apertures, first effusion apertures fluidly coupled with the first impingement apertures, and second effusion apertures fluidly coupled with the second impingement apertures. The shield quench apertures and the first effusion apertures are configured in a first axial region of the heat shield, and the second effusion apertures are configured in a second axial region of the heat shield located axially between the first axial region and a downstream end of the heat shield. A density of the first effusion apertures in the first axial region is greater than a density of the second effusion apertures in the second axial region.