Compact Swirl Quench Combustor for Altitude Relight Stability
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Solution Overview
Problem
Small gas turbine engine designs face challenges with limited altitude relight capabilities, 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, which includes a shaft connecting the turbine and compressor to facilitate compact packaging and improved cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional fuel injection system is used, then fuel delivery is achieved, but the combustor size and complexity increase
Solution Approach 1:
The fuel injection system is merged with the shaft structure itself. The shaft contains internal fuel passages that deliver fuel directly to the combustor, eliminating the need for separate external fuel injection components. This integration reduces overall combustor size and simplifies the system by combining two functions (shaft rotation and fuel delivery) into a single structural element.
Solution Approach 2:
The fuel delivery passages are nested within the shaft structure. The shaft acts as a container for the fuel system, with fuel channels embedded inside the shaft's internal geometry. This nesting approach allows the fuel injection system to occupy the same spatial envelope as the shaft, reducing the overall package size without adding external complexity.
2Reliability
If standard combustor design is used, then combustion is achieved, but altitude relight capability is limited
Solution Approach 1:
The combustor is segmented into distinct functional zones: a toroidal recirculation zone for flame stabilization and relight, a rapid quench zone for temperature control, and a lean combustion zone for efficient burning. This segmentation allows each zone to be optimized for its specific function, with the recirculation zone specifically designed to maintain combustion at high altitudes where air density is low.
Solution Approach 2:
Different regions of the combustor have different flow and temperature characteristics tailored to their function. The recirculation zone has high turbulence and recirculating flows to stabilize the flame, while the quench zone has high velocity cool flows, and the lean combustion zone has controlled stoichiometry. This local optimization enables altitude relight capability without requiring the entire combustor to be redesigned.
3Temperature
If separate cooling air system is used, then combustor liner cooling is achieved, but system complexity and space requirements increase
Solution Approach 1:
The compressor cooling air is multi-used throughout the system. It first cools the combustor liner by flowing through passages in the liner, then the same air is directed to cool the turbine blades, and finally it serves as dilution air in the combustion zone. This cascading use of a single air source eliminates the need for separate cooling systems for different components, reducing overall system complexity while maintaining effective cooling.
Solution Approach 2:
The cooling air flow is continuous and sequential rather than discrete. A single stream of compressed air continuously flows through multiple cooling functions in sequence (combustor liner → turbine → dilution), maximizing the utility of each unit of compressed air and eliminating idle or redundant cooling systems.
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 reducing the size and complexity of the combustor, enabling efficient energy recovery and compact design.
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
The rapid quench zone is configured to receive and quench with quench air combustion products from the rich combustion zone
Implementation Method 3
a toroidal recirculation zone configured to receive and combust fuel in a rich combustion zone
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 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 configured to direct a second portion of the compressed air around an outer combustor liner.