Resonator Combustor Liner Cooling
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Solution Overview
Problem
Current acoustic damping and cooling systems for turbine engine combustor liners are ineffective in cooling the entire liner, particularly the downstream sections, leading to inefficiencies and increased NOx emissions due to excessive air usage for cooling.
Innovation Solution
A resonator system with circumferentially aligned resonators and longitudinal cooling passages that provide dual-purpose cooling and purging, allowing air to efficiently cool the liner and purge internal cavities, reducing the need for excessive cooling air and improving heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is used to cool the combustor liner through resonators, then cooling effectiveness is improved, but air consumption increases leading to efficiency loss and increased NOx emissions
Solution Approach 1:
The resonator boxes are positioned at specific locations along the combustor liner where heat transfer coefficients are lowest and cooling is most needed. The system provides localized cooling enhancement rather than uniform cooling, directing cooling air precisely to the hottest sections downstream of the combustor to maximize cooling effectiveness while minimizing overall air consumption
Solution Approach 2:
Cooling air is introduced through the resonator boxes before it would naturally reach the downstream sections of the combustor liner. This preliminary action delivers cold air to the hottest sections proactively, ensuring cooling occurs at the point of maximum thermal demand rather than allowing heat accumulation first
2Temperature
If more air is used for cooling the downstream portions of the liner, then cooling coverage is improved, but NOx emissions increase
Solution Approach 1:
The resonator boxes are strategically positioned at locations where cooling is most critical (where heat transfer coefficients are lowest), providing localized cooling enhancement precisely where needed in the downstream sections. This targeted approach reduces the total amount of cooling air required compared to uniform cooling systems
Solution Approach 2:
The resonator boxes utilize the existing cooling air flow through the combustor liner and redirect it through the liner wall into the downstream sections. The system leverages the natural cooling air movement to serve the cooling function, reducing the need for additional dedicated cooling air and thereby reducing NOx emissions
3Reliability
If traditional resonator cooling is used, then acoustic damping is provided, but cooling is limited to only the portion enclosed by the resonator box
Solution Approach 1:
The resonator boxes perform dual functions: they provide acoustic damping by being tuned to specific combustion instability frequencies, and they simultaneously serve as cooling air delivery mechanisms. The same structures that dampen acoustic oscillations also channel cooling air through the liner wall to downstream sections, combining two functions in one component
Solution Approach 2:
The cooling air delivery is extended from the traditional two-dimensional plane within the resonator box enclosure into the third dimension by routing air through the liner wall itself. This allows cooling to reach downstream sections that extend beyond the physical boundaries of the resonator box, expanding the cooled area in a new spatial dimension
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 system enhances cooling efficiency by directing cold air to the hottest sections of the combustor, reduces air consumption, and allows for targeted cooling, thereby minimizing NOx emissions and improving engine performance.
Implementation Method 1
One commonly used acoustic damping device is a resonator 24, which can be a Helmholtz resonator
Implementation Method 2
air passing through the holes 32 can directly impinge on the hot surface of the liner 22, thereby providing impingement cooling to the liner 22
Implementation Method 3
the air exiting the resonator 24 through holes 38 in the liner 22 can provide a film cooling effect on the inner peripheral surface 40 of the liner 22
Implementation Method 4
A plurality of cooling passages can extend generally in a longitudinal direction within the combustor liner
Data Source
AI summary
A combustor liner has a plurality of resonators formed thereon. Each resonator has a radially outer wall and at least one side wall. The outer wall can be free of holes. Each resonator has an inner cavity defined between the outer wall, the at least one side wall and the outer peripheral surface of the liner. The at least one side wall of each resonator surrounds a subset of a plurality of holes that extend substantially radially through the liner. A plurality of cooling passages extends generally longitudinally within the liner. Each cooling passage has an inlet in fluid communication with the exterior of the liner and an outlet in fluid communication with the inner cavity of a respective one of the resonators. A coolant, such as compressor air, can enter and flow along the cooling passages to thereby cool the liner and purge the inner cavity of the resonator.