Variable Combustor Liner for Gas Turbine Emission Control
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Solution Overview
Problem
Conventional gas turbine engines have fixed combustion chamber geometries, leading to inefficient fuel burn and increased NOx emissions across varying operating states, as the primary combustion zone volume remains constant regardless of operating conditions.
Innovation Solution
Incorporating a translatable converging-diverging section in the dilution zone of the combustor liner, actuated to adjust the volume of the primary combustion zone based on power changes throughout different operating states, such as startup, takeoff, cruise, and landing, allowing for a smaller primary zone during high power operations to enhance mixing with dilution air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed combustion chamber geometry is used, then the structure is simple and reliable, but fuel efficiency decreases and NOx emissions increase across varying operating states
Solution Approach 1:
The combustor liner is divided into fixed and movable sections, where the movable section can translate axially to change the volume of the primary combustion zone. This dynamic adjustment allows the combustor to adapt to different operating states (idle, climb, cruise, descent), optimizing fuel-air mixing and combustion efficiency while reducing NOx emissions across all flight conditions.
2Device complexity
If a fixed primary combustion zone volume is used, then the device complexity is low, but fuel efficiency decreases during high power operations
Solution Approach 1:
The combustor liner is segmented into a fixed upstream section and a movable downstream section. The movable section includes a converging-diverging passage that can translate axially. This segmentation allows independent adjustment of the primary combustion zone volume without affecting the overall combustor structure, enabling optimized fuel efficiency during high power operations while maintaining structural simplicity.
3Duration of action of moving object
If the primary combustion zone volume is increased, then fuel mixing time is extended, but the mixing efficiency with dilution air decreases during high power operations
Solution Approach 1:
The movable section of the combustor liner translates axially to dynamically adjust the length of the primary combustion zone. During high power operations, the movable section retracts to shorten the primary zone, reducing the mixing period to prevent excessive fuel burn. During low power operations, it extends to lengthen the primary zone, allowing more complete mixing with dilution air. This dynamic adjustment optimizes mixing efficiency across all operating conditions.
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 solution reduces NOx emissions and improves operability by optimizing fuel efficiency and extending the mixing period of combustion gases with dilution air, thereby enhancing the overall efficiency and reducing emissions.
Implementation Method 1
Incorporating a translatable converging-diverging section in the dilution zone of the combustor liner
Implementation Method 2
a movable portion that is arranged to be actuated to adjust a percentage of the primary volume with respect to a total combustion chamber volume
Implementation Method 3
extending the mixing period of combustion gases with dilution air
Data Source
AI summary
A method of operating a combustor of a gas turbine, the combustor including a combustor liner that defines a total combustion chamber volume, and has a primary combustion zone defining a primary volume. The combustor liner includes a movable portion that is arranged to be actuated to adjust a percentage of the primary volume with respect to the total combustion chamber volume. The method includes, at a first operating state of the gas turbine, adjusting a size of the primary volume to a first percentage of the total combustion chamber volume by actuating the movable portion to adjust the size of the primary volume, and at a second operating state of the gas turbine different from the first operating state, adjusting the size of the primary volume to a second percentage of the total combustion chamber volume by actuating the movable portion to adjust the size of the primary volume.