Compact Gas Turbine Combustor With Toroidal Relight Zone
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Solution Overview
Problem
Existing small gas turbine engine designs face limitations in altitude relight capability, reverse flow designs that cool exhaust gases with combustor inlet air, large combustor packages due to fuel injection systems, and undesirably long ignitor positioning.
Innovation Solution
A gas turbine engine with a toroidal recirculation zone, rapid quench zone, and lean combustion zone, utilizing additive manufacturing for construction, features a shaft to transmit rotational energy and pump fuel, and includes combustor inlet vanes for tangential momentum and ignitor positioning for efficient combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a traditional fuel injection system is used, then fuel can be delivered to the combustor, but the combustor package size becomes large
Solution Approach 1:
The fuel injection system is merged with the rotating shaft assembly. The shaft serves dual functions: transmitting rotational energy from the turbine to the compressor and simultaneously serving as the fuel injection system. Fuel is delivered through fuel ports in the shaft, eliminating the need for separate fuel injection components and reducing overall combustor package size.
Solution Approach 2:
The rotating shaft is designed with multi-functionality, serving as both the power transmission component and the fuel delivery system. The shaft includes fuel ports and fuel injector air ports integrated into its structure, allowing it to perform both mechanical power transmission and fuel injection functions simultaneously.
2Length of moving object
If the ignitor is positioned further from the fuel injector, then ignition can occur, but the combustor becomes longer
Solution Approach 1:
A toroidal recirculation zone is introduced as an intermediary region between the fuel injector and the ignitor. This recirculation zone creates a controlled environment where the air-fuel mixture circulates and prepares for reliable ignition, allowing the ignitor to be positioned closer to the fuel injector while maintaining ignition reliability.
3Temperature
If exhaust gases are cooled by combustor inlet air, then cooling is achieved, but energy recovery is reduced
Solution Approach 1:
The air supply system is segmented into distinct zones with different functions. Primary inlet air is directed to the toroidal recirculation zone for fuel combustion, while secondary inlet air is directed to the exhaust gas cooling zone. This segmentation allows independent optimization of combustion efficiency and exhaust cooling without compromising energy recovery.
Solution Approach 2:
Different regions of the combustor are provided with different air flow characteristics tailored to their specific functions. The toroidal recirculation zone receives primary inlet air for rich combustion, while the exhaust cooling zone receives secondary inlet air for controlled cooling of exhaust gases, maintaining local quality and function throughout the combustor.
4Volume of moving object
If a compact combustor design is used, then size is reduced, but altitude relight capability may be compromised
Solution Approach 1:
The toroidal recirculation zone creates a dynamic, self-sustaining flow pattern that adapts to varying operating conditions including altitude changes. The swirling flow and recirculation characteristics remain effective across different altitudes, enabling the compact combustor to maintain reliable operation and relight capability from sea level to high altitude 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
Enhances altitude relight capability, improves operability, reduces combustor size, and extends operational life while maintaining efficient energy recovery and cooling.
Implementation Method 1
a toroidal recirculation zone configured to receive and combust fuel in a rich combustion zone
Implementation Method 2
a rapid quench zone downstream of the toroidal recirculation zone, wherein the rapid quench zone is configured to receive and quench with quench air combustion products from the rich combustion zone
Implementation Method 3
a lean combustion zone downstream of the rapid quench zone, and configured to complete combustion of the fuel and to generate hot combustor exhaust gas
Implementation Method 4
a cooling air flow path configured to direct a second portion of the compressed air around an outer combustor liner to cool the combustor liner
Implementation Method 5
a plurality of combustor inlet vanes positioned at an inlet to the toroidal recirculation zone. The plurality of combustor inlet vanes are configured to impart a desired tangential momentum to combustor primary inlet air as it enters the rich combustion zone
Implementation Method 6
A shaft, which mechanically connects a turbine and the compressor through an annular space formed by the combustor surrounding the shaft, is configured to transmit rotational energy from the turbine to the compressor
Implementation Method 7
through a plurality of fuel injectors configured to mix fuel and fuel injector air to form the air/fuel mixture in the rich combustion zone
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A gas turbine engine (100a; 100b) includes a compressor (102) configured to receive inlet air at a compressor inlet (102a) and generate compressed air at a compressor exit (102b), a combustor (104) positioned fluidically and physically downstream of the compressor (102), a turbine (108) positioned fluidically and physically downstream of the combustor (104), and a shaft (110) mechanically connecting the turbine (108) and the compressor (102). The combustor (104) is fluidically connected to the compressor (102) to receive a first portion of the compressed air (130) as combustor primary inlet air (130a). The combustor (104) includes a toroidal recirculation zone configured to receive and combust fuel in a rich combustion zone (104a), an ignitor positioned to ignite an air/fuel mixture in the rich combustion zone (104a), a rapid quench zone (104b) downstream of the toroidal recirculation zone, a lean combustion zone (104c) downstream of the rapid quench zone (104b), and a cooling air flow path configured to direct a second portion (130b) of the compressed air (130) around an outer combustor liner.