Asymmetrical Perforation Flow Conditioner for Combustor Airflow
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Solution Overview
Problem
Gas turbine engines with can-annular burner-type combustors face non-uniform airflow patterns across the air inlet plane, leading to temperature differentials and increased emissions of NOx and CO due to asymmetrical airflow distribution among premixers, which existing symmetrical perforation patterns fail to adequately address.
Innovation Solution
Implementing flow conditioners with locally varying, asymmetrical patterns of circumferential perforations to regulate airflow and achieve uniform fuel-air mixture across the burner's air inlet plane, tailored for individual burner locations within the combustor section annular ring to mitigate non-uniform thru-flow variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If symmetrical perforation patterns are used in flow conditioners, then manufacturing simplicity and uniform airflow distribution are achieved, but non-uniform thru-flow variations among different burners in the annular ring cannot be mitigated
Solution Approach 1:
The flow conditioner employs locally varying perforation patterns where different circumferential zones have different perforation densities, sizes, or shapes. This local differentiation allows each zone to compensate for specific non-uniform airflow characteristics at corresponding burner locations, achieving uniform airflow distribution across all burners while maintaining a relatively simple overall structure.
Solution Approach 2:
The invention transitions from symmetrical perforation patterns to asymmetrical patterns that are specifically designed to counteract the non-uniform airflow distribution in the annular combustor. The asymmetrical pattern is tailored to the specific geometric and flow characteristics of the combustor, allowing precise control over airflow distribution to different burners.
2Reliability
If uniform airflow distribution is achieved across the air inlet plane, then consistent combustion performance and reduced emissions are obtained, but complex locally varying perforation patterns are required
Solution Approach 1:
Rather than applying a complex uniform modification across the entire flow conditioner, the invention applies localized variations in perforation characteristics only in specific circumferential zones where airflow non-uniformity occurs. This approach achieves the desired combustion performance consistency while minimizing the overall complexity of the perforation pattern design.
Solution Approach 2:
The flow conditioner perimeter is divided into multiple circumferential zones, each with its own optimized perforation pattern. This segmentation allows independent optimization of each zone to address local airflow issues, achieving global airflow uniformity through coordinated local adjustments rather than a single complex pattern.
3Manufacturing precision
If locally varying asymmetrical perforation patterns are implemented, then non-uniform thru-flow variations are mitigated and combustion uniformity is enhanced, but manufacturing complexity increases
Solution Approach 1:
The invention focuses perforation pattern variations only in specific local zones where airflow non-uniformity is detected, rather than applying complex patterns across the entire flow conditioner. This localized approach maintains manufacturing simplicity in the majority of the structure while achieving precise airflow control where needed.
Solution Approach 2:
The invention modifies specific parameters of the perforation pattern (such as perforation diameter, spacing, or density) in localized zones rather than changing the overall pattern complexity. These parameter adjustments are made to match the specific airflow characteristics at different circumferential positions, achieving precise flow control with relatively simple manufacturing modifications.
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 approach ensures consistent combustion performance, reduces combustion flare-ups, and meets emission specifications by normalizing airflow rates across all premixers, thereby enhancing engine combustion uniformity and reducing potential damage to combustor components.
Implementation Method 1
The flow conditioner defines an asymmetrical pattern of circumferential perforations that vary circumferential airflow locally from outside the basket into the airflow reversal region
Data Source
AI summary
Can-annular burners for gas turbine engines with flow conditioners having locally varying, asymmetrical patterns of circumferential perforations, to promote uniform fuel-air mixture among all premixers in the burner basket. Any one or more of the perforation pattern, pattern density, perforation profiles and perforation cross sectional area is locally varied to alter circumferential airflow into the burner basket, which in turn mitigates non-uniform thru-flow variations across the burner's air inlet plane. In some embodiments, the flow conditioner asymmetric perforation patterns are tailored for individual burner locations within the engine's combustor section annular ring, which mitigates non-uniform thru-flow variation among different respective burners in the combustor section annular ring. Thru-flow uniformity within each burner and among all the combustor section burners promotes uniform engine combustion.