Fuel Injection Boss Cooling Circuit for Combustor Hardware Life
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Solution Overview
Problem
AFS systems in gas turbine combustors face issues with boss degradation due to exposure to high temperature combustion gases, leading to reduced hardware life.
Innovation Solution
A fuel injector assembly with a boss featuring a cooling circuit that includes a post-impingement plenum and film cooling channels to protect against high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the boss is exposed to high temperature combustion gases for fuel injection, then the fuel injection function is achieved, but the boss and fuel injector suffer thermal damage and reduced hardware life
Solution Approach 1:
The cooling system is segmented into multiple functional zones: an inlet plenum receiving cooling air, a pre-impingement plenum directing air through impingement channels, and a post-impingement plenum distributing air through film cooling holes. This segmentation allows different cooling mechanisms to work in sequence, effectively protecting the boss from thermal damage while maintaining structural integrity and extending hardware life.
2Object-affected harmful factors
If thermal barrier coating is applied to protect the boss, then thermal protection is improved, but spallation occurs under high temperature and thermal stress
Solution Approach 1:
Active cooling air flows are established before the thermal barrier coating reaches its thermal limits. The cooling system pre-cools the boss surface through impingement and film cooling mechanisms, preventing excessive thermal buildup that would cause coating spallation. This preliminary cooling action protects the coating integrity while maintaining thermal protection.
3Temperature
If a cooling circuit is added to the boss, then thermal protection is improved, but the device complexity increases
Solution Approach 1:
The cooling circuit is merged with the boss structure itself, with cooling channels and plenums integrated into the boss geometry. The impingement channels and film cooling holes are formed as part of the boss manufacturing process, combining the structural and cooling functions into a single integrated component. This reduces overall device complexity while providing effective thermal management.
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 cooling circuit effectively extends the useful life of the boss and fuel injector by maintaining thermal resistance against combustion gases, preventing spallation of thermal barrier coatings.
Implementation Method 1
The cooling circuit may include a inlet plenum, a pre-impingement plenum, an impingement plate, a post-impingement plenum, and a array of film cooling holes
Implementation Method 2
The boss defines a cooling circuit that includes a post-impingement plenum defined in the inner flange between an inner wall of the inner flange and an impingement plate in cooling proximity to the inner wall
Implementation Method 3
a plurality of film cooling channels that are defined in the inner flange and that fluidly couple the post-impingement plenum to the combustion chamber
Data Source
AI summary
A combustor includes a combustion liner that defines a combustion chamber and an outer sleeve spaced apart from the combustion liner, such that an annulus is defined between the combustion liner and the outer sleeve. The combustor further includes a fuel injection assembly having a boss coupled to at least one of the combustion liner and the outer sleeve. The boss includes an inner flange coupled to the combustion liner, an outer flange, and a body extending between the outer flange and the inner flange. The boss defines a cooling circuit having a post-impingement plenum defined in the inner flange between an inner wall of the inner flange and an impingement plate in cooling proximity to the inner wall; and a plurality of film cooling channels that are defined in the inner flange and fluidly couple the post-impingement plenum to the combustion chamber.