Combustion Liner Bias Effusion Cooling
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Solution Overview
Problem
Non-uniform distribution of cooling air around the combustion liner in gas turbine engines leads to adverse consequences for structural integrity and operating life due to uneven cooling.
Innovation Solution
A combustion liner design with a higher concentration of cooling holes in the lower portion, arranged in axially spaced rows, and oriented at surface and tangential angles to enhance cooling effectiveness, redistributing and utilizing existing cooling air more efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is provided along the outer surface and through the wall thickness of the combustion liner, then the combustion liner is cooled, but non-uniform distribution of cooling air leads to non-uniform cooling and adverse consequences to structural integrity
Solution Approach 1:
The patent applies local quality by varying the concentration of cooling holes in different regions of the combustion liner. The lower portion, which experiences higher temperatures and greater thermal stress, has a higher concentration of cooling holes (three sets of axially spaced rows), while the upper portion has a lower concentration (one set of axially spaced rows). This non-uniform distribution optimizes cooling effectiveness in the most critical thermal zones while maintaining structural integrity throughout the liner.
Solution Approach 2:
The patent employs asymmetry by creating an asymmetric distribution of cooling holes that does not uniformly spread around the entire combustion liner. Instead, the cooling holes are concentrated asymmetrically in the lower portion where thermal loads are highest, with the third set of axially spaced rows positioned to provide enhanced cooling where needed. This asymmetric approach addresses the non-uniform thermal environment more effectively than symmetric distribution would.
2Temperature
If a higher concentration of cooling holes is provided in the lower portion, then cooling effectiveness is improved, but the complexity of the cooling hole arrangement increases
Solution Approach 1:
The patent applies segmentation by dividing the combustion liner into distinct zones with different cooling hole concentrations. The lower portion is segmented into three sets of axially spaced rows, while the upper portion has one set of axially spaced rows. This segmentation allows optimized cooling in the lower portion without requiring complex cooling arrangements throughout the entire liner, thus balancing cooling effectiveness with manufacturing complexity.
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
Improves cooling effectiveness and reduces temperature gradients within the combustion liner, enhancing structural integrity and operating life by optimizing the distribution and orientation of cooling holes.
Implementation Method 1
Cooling air is typically provided along the outer surface of the combustion liner and often times through the wall thickness and along at least a portion of the inner wall of the combustion liner
Implementation Method 2
Cooling air is typically provided along the outer surface of the combustion liner and often times through the wall thickness
Data Source
AI summary
A system and method for improving the cooling to a portion of a combustion liner of a gas turbine combustor is disclosed. The combustion liner is cooled by supplying air through a plurality of cooling holes arranged in axially spaced rows in an upper and lower portion of the liner. The cooling holes are spaced accordingly so as to direct additional cooling flow to an area of the combustion liner not receiving sufficient flow due to maldistributions of air from the compressor discharge.