Gas Turbine Combustor Dilution Slot Frame Design
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Solution Overview
Problem
Conventional gas turbine combustors face challenges in reducing NOx emissions due to the formation of hot spots within the combustion chamber, which are not adequately addressed by the discrete jets of dilution air provided by traditional dilution holes.
Innovation Solution
The combustor design incorporates a dilution slot frame with a plurality of dilution slots arranged to form an annular ring of dilution air, combined with a fence that directs the dilution air toward the center of the combustion chamber, increasing turbulence and uniform mixing, thereby reducing NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If discrete dilution holes are used to supply dilution air, then the combustion chamber can receive additional air to mix with combustion products, but hot spots form and NOx emissions are not adequately reduced
Solution Approach 1:
The combustor liner is segmented into multiple sections with dilution slots positioned at different locations. Each segment supplies dilution air to specific zones, creating a distributed cooling effect that prevents localized hot spots while maintaining overall temperature control for NOx reduction
Solution Approach 2:
Dilution slots are strategically positioned to provide localized dilution air supply where hot spots are most likely to form. The slot geometry and positioning create region-specific temperature control, delivering cooler air precisely where needed to eliminate hot spots without affecting other combustion zones
2Device complexity
If dilution holes are spaced apart around the circumference, then the structure is simpler, but the mixing of dilution air and combustion gases is insufficient
Solution Approach 1:
The invention transitions from point-like dilution holes to elongated dilution slots that extend in the circumferential direction. This dimensional change creates an annular ring configuration that provides continuous circumferential coverage, improving mixing uniformity while maintaining structural simplicity through the slot geometry rather than increased component count
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 configuration effectively reduces NOx emissions by preventing hot spot formation and enhancing the mixing of dilution air and combustion gases, leading to a greater reduction in nitrogen oxide emissions compared to conventional combustors.
Implementation Method 1
increasing turbulence and uniform mixing
Implementation Method 2
dilution air to the combustion chamber to mix with the combustion products
Implementation Method 3
a fence that directs the dilution air toward the center of the combustion chamber
Implementation Method 4
supply additional air to the combustion chamber to mix with the combustion products coming from the primary zone
Data Source
AI summary
A combustor for a gas turbine engine includes a forward liner segment and an aft liner segment positioned downstream from the forward liner segment relative to a direction of flow through the combustor. The forward and aft liner segments at least partially define a combustion chamber. Furthermore, the combustor includes a dilution slot frame positioned between the forward and aft liner segments along a longitudinal centerline of the gas turbine engine. Moreover, the dilution slot frame defines a plurality of dilution slots spaced apart from each other along a circumferential direction of the gas turbine engine such that the plurality of dilution slots provides an annular ring of dilution air to the combustion chamber.