Combustor Liner Shaft Fuel Injection for Compact Altitude Relight
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Solution Overview
Problem
Small gas turbine engines face challenges with combustor designs that limit altitude relight capabilities, reverse flow designs that decrease energy recovery, and fuel injection systems that require larger packages and separate pumps, along with undesirably long ignitor positioning.
Innovation Solution
A gas turbine engine design featuring a toroidal recirculation zone, rapid quench zone, and lean combustion zone, integrated with a shaft for fuel injection and cooling, using additive manufacturing for compact construction, and a shaft cooling air pump for efficient fuel and air distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a separate fuel pump and manifold system is used, then fuel distribution can be achieved, but the device size increases and packaging becomes more complex
Solution Approach 1:
The fuel pump is integrated directly into the rotating shaft assembly, combining the fuel delivery function with the existing mechanical structure. The shaft-mounted pump eliminates the need for separate fuel pump housing and manifold assemblies, reducing overall packaging volume while maintaining fuel distribution capability to multiple injectors.
Solution Approach 2:
The rotating shaft serves multiple functions: it transmits mechanical power from the turbine, houses the fuel pump mechanism, and positions fuel injectors at the combustor inlet. This multi-functional design eliminates the need for separate structural components, reducing device complexity and improving packaging efficiency.
2Reliability
If traditional combustor designs are used, then combustion can occur, but altitude relight capability is limited
Solution Approach 1:
The combustor design incorporates dynamic flow control features including a variable geometry recirculation zone and adjustable airflow paths that adapt to different operating conditions. The toroidal recirculation zone creates a dynamic mixing pattern that enhances flame stability at high altitudes while maintaining efficient combustion at sea level.
Solution Approach 2:
The system utilizes variable air-to-fuel ratios and adjustable quenching parameters to optimize combustion across different altitudes. The rapid quench zone can be adjusted to control flame temperature and propagation speed, enabling reliable relight capability from idle to full power across the entire operating range including high altitude conditions.
3Ease of operation
If reverse flow design is used, then airflow can be managed, but energy recovery decreases
Solution Approach 1:
Instead of using a reverse flow design where exhaust gases flow backward through the combustor, this invention employs a forward-flowing exhaust system where hot gases move directly from the combustor through the turbine to the exhaust. This inversion of the flow concept maintains effective airflow management while maximizing energy recovery in the turbine expansion process.
4Reliability
If ignitor is positioned far from fuel injection point, then ignition can occur, but the overall length increases
Solution Approach 1:
The ignitor is integrated into the fuel injection assembly itself, merging the ignition function with the fuel delivery mechanism. This eliminates the need for a separate, remotely positioned ignitor and reduces the overall length of the combustor inlet assembly while maintaining reliable ignition of the fuel-air mixture.
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 compact packaging, and ensures efficient energy recovery through integrated fuel injection and cooling, promoting durability and airflow.
Implementation Method 1
A shaft cooling air pump is configured to further compress and accelerate the second portion of the compressed air before the second portion of the compressed air enters the combustor as fuel injector air and combustor secondary inlet air
Implementation Method 2
a toroidal recirculation zone configured to receive and combust fuel in a rich combustion zone
Implementation Method 3
an ignitor positioned to ignite an air/fuel mixture in the rich combustion zone
Implementation Method 4
a rapid quench zone downstream of the toroidal recirculation zone... configured to receive and quench with quench air combustion products from the rich combustion zone
Implementation Method 5
a lean combustion zone downstream of the rapid quench zone... configured to complete combustion of the fuel and to generate hot combustor exhaust gas
Implementation Method 6
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
Data Source
AI summary
A gas turbine engine includes 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. The combustor 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 configured to direct a second portion of the compressed air around an outer combustor liner.