Hydrogen Gas Turbine Combustor Size Rating and NOx Control
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Solution Overview
Problem
Hydrogen fuel in gas turbine engines produces higher combustion temperatures and increased NOx emissions due to its high reactivity, requiring a combustor design that reduces residence time and meets NOx emission targets, which existing designs fail to effectively address.
Innovation Solution
The development of combustors with specific burner length and dome height ratios, along with dilution openings to control flame structure and temperature distribution, allowing for efficient combustion of hydrogen fuel while minimizing NOx production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hydrogen fuel is used in gas turbine engines, then combustion efficiency is improved, but NOx emissions increase due to higher combustion temperatures
Solution Approach 1:
The combustor is divided into multiple zones including a primary combustion zone, a dilution zone with dilution openings, and a secondary combustion zone. This segmentation allows different regions to perform different functions: the primary zone maintains high temperature for efficient hydrogen combustion, while the dilution zone introduces cooler air to reduce peak temperatures and NOx formation in the secondary zone.
Solution Approach 2:
Different regions of the combustor are designed with different properties: the primary combustion zone has a specific geometry (burner length and dome height ratios) optimized for hydrogen flame propagation, while the dilution zone introduces cooler air at specific locations to create localized temperature reduction zones that suppress NOx formation without compromising overall combustion efficiency.
2Object-generated harmful factors
If combustor residence time is reduced to meet NOx emission targets, then NOx emissions are reduced, but combustion stability may be compromised
Solution Approach 1:
The primary combustion zone is designed with specific geometric ratios (burner length to diameter, and dome height to diameter) that pre-condition the hydrogen-air mixture for stable flame propagation before the gases enter the dilution zone. This preliminary configuration ensures that combustion is well-established and stable before temperature reduction occurs.
Solution Approach 2:
The dilution air introduced through dilution openings acts as an intermediary substance that gradually reduces temperature and extends residence time. This intermediary approach allows temperature control and emission reduction without creating abrupt changes that would destabilize the combustion process.
3Object-generated harmful factors
If dilution openings are added to control temperature distribution, then NOx emissions are reduced, but device complexity increases
Solution Approach 1:
The dilution openings are integrated into the combustor liner as porous structures or arrays of small holes that allow controlled air ingestion. This approach achieves temperature control and NOx reduction through the geometry and distribution of openings rather than complex mechanical systems, maintaining relative simplicity while achieving the desired thermal management.
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 proposed design effectively reduces NOx emissions and extends the lifespan of turbine engine components by optimizing flame propagation and temperature control within the combustor.
Implementation Method 1
hydrogen fuel is mixed with compressed air and combusted to produce combustion gases
Implementation Method 2
control flame structure and temperature distribution
Data Source
AI summary
A gas turbine engine includes a hydrogen fuel delivery assembly configured to deliver a hydrogen fuel flow, a compressor section configured to compress air flowing therethrough to provide a compressed air flow, and a combustor including a combustion chamber having a burner length and a burner dome height. The combustion chamber is configured to combust a mixture of the hydrogen fuel flow and the compressed air flow. The combustion chamber can be characterized by a combustor size rating between one inch and seven inches. In more detail, the combustion chamber can be characterized by the combustor size rating between one inch and seven inches at a core air flow parameter between two and one half kN and sixty kN, in which the combustor size rating is a function of the core air flow parameter.