Compact Toroidal Combustor Layout for Altitude Relight
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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, fuel injection systems requiring larger packages, and ignitor positioning that results in undesirably long combustors.
Innovation Solution
A gas turbine engine design featuring a toroidal recirculation zone, rapid quench zone, and lean combustion zone with integrated ignitor, utilizing additive manufacturing for compact construction, and a shaft cooling air pump for efficient fuel and air distribution, reducing unwanted heat exchange and promoting compact packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional combustor design is used, then the combustor can be manufactured with traditional processes, but the size is larger and altitude relight capability is limited
Solution Approach 1:
The combustor is divided into distinct functional zones (rich combustion zone, rapid quench zone, lean combustion zone) with specific geometric configurations. This segmentation allows each zone to be optimized for its specific function while enabling compact overall packaging, directly addressing the need for smaller combustor size with improved altitude relight capability.
Solution Approach 2:
The design transitions from conventional linear combustion zones to a toroidal (donut-shaped) recirculation zone, utilizing three-dimensional space more effectively. This dimensional change allows the combustion process to occur in a compact volume while maintaining the necessary flow paths and heat transfer surfaces, reducing overall combustor size.
2Temperature
If reverse flow design is used to cool exhaust gases, then cooling efficiency improves, but combustor inlet air is cooled reducing energy available for turbine
Solution Approach 1:
The cooling function is extracted from the exhaust gas stream and implemented through a separate cooling air flow path that circulates around the outer combustor liner. This allows the exhaust gases to be cooled independently without mixing with the combustor inlet air, preventing the energy loss that would occur if reverse flow cooling were used.
Solution Approach 2:
A dedicated cooling air flow path acts as an intermediary between the compressed air source and the combustor liner cooling requirement. This intermediate cooling system provides the necessary heat transfer without directly cooling the exhaust gases, thereby preserving the energy available for the turbine.
3Device complexity
If fuel injection system is simplified, then device complexity reduces, but altitude relight capability is compromised
Solution Approach 1:
The fuel injection system is merged with the shaft structure, where the shaft itself serves as the fuel delivery mechanism. This integration reduces the number of separate components while maintaining the capability to provide precise fuel distribution at various altitudes, achieving both simplified complexity and preserved altitude relight capability.
Solution Approach 2:
The system utilizes changes in operating parameters (pressure, temperature, air density) to maintain effective fuel injection and combustion across different altitudes. By designing the fuel delivery and combustion zones to respond to these parameter changes, the system achieves altitude relight capability without requiring a complex adjustable fuel injection system.
4Productivity
If ignitor is positioned to improve combustion, then combustion efficiency increases, but combustor length increases
Solution Approach 1:
The ignitor and combustion zones are arranged in a curved, toroidal configuration rather than a linear arrangement. This curvature allows the ignitor to be positioned optimally for combustion efficiency while the three-dimensional arrangement compresses the overall length of the combustor, achieving both improved combustion efficiency and reduced combustor length.
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 with flame stability, and extends operational life while maintaining a compact size, utilizing additive manufacturing for efficient combustor cooling and fuel distribution.
Implementation Method 1
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 2
a toroidal recirculation zone configured to receive and combust fuel in a rich combustion zone
Implementation Method 3
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 4
a shaft cooling air pump configured to further compress the second portion of the compressed air before the second portion of the compressed air enters the combustor
Data Source
AI summary
A gas turbine engine include a compressor configured to receive inlet air at a compressor inlet and generate compressed air at a compressor exit, a combustor positioned fluidically and physically downstream of the compressor, a turbine positioned fluidically and physically downstream of the combustor, and a shaft mechanically connecting the turbine and the compressor. The combustor is fluidically connected to the compressor to receive a first portion of the compressed air as combustor primary inlet air and also includes a toroidal recirculation zone configured to receive and combust fuel in a rich combustion zone, an ignitor positioned to ignite an air/fuel mixture in the rich combustion zone, a rapid quench zone downstream of the toroidal recirculation zone, a lean combustion zone downstream of the rapid quench zone, and a cooling air flow path.