Gas Turbine Combustor Dilution Slot and Fence Design
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Solution Overview
Problem
Conventional gas turbine combustors face challenges in achieving effective mixing of dilution air with combustion gases, leading to inadequate reduction of NOx emissions and inefficient combustion processes.
Innovation Solution
The combustor design incorporates dilution slots that provide an annular ring of dilution air and a fence to increase turbulence, along with a guide feature to redirect cooling medium, enhancing mixing and combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If dilution holes are used to supply additional air to the combustion chamber, then NOx emissions are reduced, but the mixing with combustion gases is insufficient
Solution Approach 1:
The dilution air supply is segmented into multiple dilution slots positioned at different locations around the combustion chamber, allowing distributed injection of dilution air to improve mixing effectiveness while maintaining NOx reduction
Solution Approach 2:
A fence structure is introduced as an intermediary element between the dilution slots and combustion chamber, creating turbulence that enhances mixing between dilution air and combustion gases, thereby resolving the insufficient mixing problem while preserving the NOx emission reduction benefit
2Temperature
If cooling medium is used to cool the liner, then liner temperature is reduced, but the cooling medium does not effectively mix with combustion gases
Solution Approach 1:
The cooling medium serves dual functions: it cools the liner through the cooling channels and simultaneously acts as dilution air when redirected through guides into the combustion chamber, eliminating waste and improving overall combustion efficiency
Solution Approach 2:
The cooling medium flow is redirected through guides to create a feedback loop where the cooled air re-enters the combustion chamber to participate in combustion, creating a closed-loop system that improves both cooling effectiveness and combustion efficiency
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 design reduces NOx emissions and improves engine performance by ensuring quicker and more uniform mixing of dilution air with combustion products, resulting in a more efficient combustion process.
Implementation Method 1
one or more guides configured to redirect cooling medium into the dilution slot
Implementation Method 2
The dilution holes, in turn, supply additional air to the combustion chamber to mix with the combustion products coming from the primary zone of the combustion chamber and complete the combustion process rapidly, thereby reducing NOx (oxides of nitrogen) emissions
Implementation Method 3
a fence to increase turbulence, along with a guide feature to redirect cooling medium, enhancing mixing and combustion efficiency
Implementation Method 4
a scooped interface configured to redirect cooling medium into the dilution slot, the scooped interface defining a scooped surface configured to form a film of airflow into the combustor
Data Source
AI summary
A combustor for a gas turbine engine, the gas turbine engine defining a longitudinal centerline extending in a longitudinal direction, a radial direction extending orthogonally outward from the longitudinal centerline, and a circumferential direction extending concentrically around the longitudinal centerline, the combustor including: a liner at least partially defining a combustion chamber, the liner including a dilution slot in fluid communication with the combustion chamber; and one or more guides configured to redirect cooling medium into the dilution slot.