Gas Turbine Combustor Steam Injection Plenum
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Solution Overview
Problem
Existing combustor designs for gas turbine engines face challenges in reducing carbon monoxide (CO) and nitrous oxide (NOx) emissions, as direct injection of steam into the swirler can lead to flameout conditions or reduce combustion efficiency.
Innovation Solution
The design incorporates steam channels and nozzles within a cowl surrounding the swirler assembly, allowing steam to mix with compressed air in a plenum before entering the combustion chamber, thereby increasing the water-to-air ratio and reducing NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If steam is injected directly into the swirler via fuel nozzle, then CO and NOx emissions are reduced, but flameout conditions occur and combustion efficiency decreases
Solution Approach 1:
The steam injection system is segmented into multiple injection locations: some steam is injected directly into the swirler via fuel nozzles, while additional steam is injected into the plenum chamber before the swirler. This segmentation allows different steam quantities to be delivered through different pathways, enabling flame stabilization while reducing emissions.
Solution Approach 2:
The plenum chamber acts as an intermediary between the steam source and the combustion chamber. Steam injected into the plenum mixes with compressed air in this intermediate space, creating a pre-mixed steam-air mixture that is then delivered to the combustion chamber, preventing direct steam-fuel contact that causes flameout.
2Object-generated harmful factors
If more steam is injected into the combustor, then NOx emissions are reduced, but combustion efficiency decreases
Solution Approach 1:
Different regions of the combustor receive different steam concentrations. The plenum chamber receives a higher steam concentration for emission reduction, while the swirler assembly receives a controlled steam amount to maintain combustion efficiency. This local differentiation allows optimized performance in each zone.
Solution Approach 2:
The system changes the physical state and concentration parameters of steam delivery by injecting steam at different locations and in different quantities. By controlling the steam-to-air ratio in the plenum versus the steam-to-fuel ratio at the swirler, the system optimizes both emission reduction and combustion efficiency through parameter adjustment.
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 approach enables a greater reduction in NOx emissions by allowing more steam to be injected into the combustor, improving combustion efficiency and reducing harmful emissions.
Implementation Method 1
steam to mix with compressed air in a plenum before entering the combustion chamber
Implementation Method 2
steam channels and nozzles within a cowl surrounding the swirler assembly, allowing steam to mix with compressed air in a plenum
Implementation Method 3
a swirler that provides a flow of swirled air mixed with fuel into a combustion chamber
Implementation Method 4
the fuel and air mixture is ignited and burned. The burning of the fuel and air mixture in the combustion chamber results in carbon monoxide (CO) and nitrous oxide (NOx) emissions
Data Source
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AI summary
A combustor (26) for an aircraft gas turbine engine (10) includes a dome structure (134), a swirler assembly (156, 156a, 156b) connected with the dome structure (134), and a cowl (152, 152a, 152b, 152c, 152d, 152e, 152f, 152g, 152') connected with the dome structure (134) and defining a plenum (154, 154a, 154b) between the dome structure (134) and the cowl (152, 152a, 152b, 152c, 152d, 152e, 152f, 152g, 152'), and surrounding the swirler assembly (156, 156a, 156b). The cowl (152, 152a, 152b, 152c, 152d, 152e, 152f, 152g, 152') includes an airflow opening (157, 157a, 157b) through an upstream wall portion (12, 192a, 192b) of the cowl (152, 152a, 152b, 152c, 152d, 152e, 152f, 152g, 152') for providing a flow of compressed air (172) into the plenum (154, 154a, 154b). In addition, the cowl (152, 152a, 152b, 152c, 152d, 152e, 152f, 152g, 152') includes a cowl steam channel (198) therewithin and a plurality of steam injection nozzles (200, 218, 230, 236, 244, 248, 274, 276, 294, 296, 306, 308) that provide a flow of steam (114, 120) from the cowl steam channel (198) into the plenum (154, 154a, 154b).