Compact Gas Turbine Combustor With Toroidal Recirculation Relight

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Solution Overview

Problem

Existing small gas turbine engine designs face limitations in altitude relight capability due to limited height recirculation zones, inefficient fuel distribution systems that increase size, and undesirably long combustors with poor ignitor positioning, along with issues in cooling and energy recovery.

Innovation Solution

A compact gas turbine engine design incorporating a toroidal recirculation zone, rapid quench zone, and lean combustion zone with integrated shaft cooling and fuel injection, utilizing additive manufacturing for construction, to enhance flame stability, reduce size, and improve operability and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If traditional fuel distribution systems are used, then fuel can be delivered to the combustor, but the system size increases and complexity increases

Engineering Contradiction:
Improvecombustor sizeVSAvoidfuel distribution system complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The fuel distribution system is merged with the combustor structure itself. The combustor liner incorporates fuel injection ports and cooling passages integrated into its walls, eliminating the need for separate external fuel distribution components. This integration reduces overall system size and complexity while maintaining effective fuel delivery to the combustion zone.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The combustor liner serves multiple functions simultaneously: it acts as the combustion chamber boundary, provides cooling passages for thermal management, and incorporates fuel injection ports for fuel delivery. This multi-functionality eliminates the need for separate dedicated components for each function, reducing system size and complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If the combustor is designed with adequate cooling, then the combustor liner can withstand high temperatures, but the system size and complexity increase

Engineering Contradiction:
Improvecombustor liner temperature resistanceVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling system is merged with the combustor liner structure. Cooling passages are built directly into the liner walls, allowing coolant flow through the liner thickness to absorb heat from the combustion side and dissipate it to the exterior. This integration provides adequate cooling without requiring separate external cooling systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The combustor liner simultaneously serves as the combustion chamber boundary and as the cooling system. The liner's wall structure incorporates internal cooling passages that provide thermal management, eliminating the need for separate dedicated cooling components and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If a separate fuel pump and manifold are used, then fuel can be pumped and distributed, but the combustor package size becomes larger than desired

Engineering Contradiction:
Improvefuel pumping capabilityVSAvoidcombustor package size
Core Design Contradiction:
ProductivityVSVolume of moving object

Solution Approach 1:

The fuel pump function is merged with the rotating shaft. The shaft incorporates fuel injection ports that deliver fuel directly to the combustion zone, and the rotation of the shaft provides the pumping action to move fuel through the system. This eliminates the need for separate external fuel pump and manifold components, significantly reducing combustor package size.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotating shaft simultaneously serves as the mechanical connection between turbine and compressor, the fuel delivery mechanism, and the pumping system. This multi-functionality consolidates multiple components into one, eliminating the need for separate fuel pump and manifold while maintaining effective fuel pumping and distribution capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Volume of moving object

If the recirculation zone height is limited, then the combustor can be more compact, but altitude relight capability is reduced

Engineering Contradiction:
Improvecombustor sizeVSAvoidaltitude relight capability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The combustor design creates a localized toroidal recirculation zone with specific geometric characteristics that maximize flame stability and relight capability within a compact volume. The toroidal shape with its characteristic vortex structure enhances fuel-air mixing and flame anchoring in a confined space, providing altitude relight capability without requiring a large recirculation zone height.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The recirculation zone is designed with a toroidal (doughnut-shaped) geometry that utilizes curved flow paths and vortex structures to enhance mixing and flame stability. This curved, three-dimensional structure maximizes the recirculation effectiveness within a compact volume, providing reliable altitude relight capability without increasing overall combustor size.

Inventive Principle:
Principle #14Spheroidality (Curvature)

5Volume of moving object

If the combustor is designed for compact packaging, then the overall engine size is reduced, but ignitor positioning becomes poor

Engineering Contradiction:
Improvecombustor sizeVSAvoidignitor positioning
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The ignitor is merged with the combustor liner structure. The ignitor is positioned within the liner wall or integrated into the fuel injection system, allowing it to be properly located in the combustion zone without requiring additional external space. This integration maintains effective ignitor positioning for reliable ignition while supporting compact combustor packaging.

Inventive Principle:
Principle #5Merging (Combining)

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

The design achieves improved altitude relight capability, compact packaging, and enhanced operational life with efficient fuel distribution and cooling, maximizing energy recovery and flame stability.

Implementation Method 1

a toroidal recirculation zone configured to receive and combust fuel in a rich combustion zone

Methodology Applied
Scientific EffectCombustion: Combustion

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

Methodology Applied
Scientific EffectQuenching: Cooling

Implementation Method 3

a lean combustion zone downstream of the rapid quench zone, wherein the lean combustion zone is configured to complete combustion of the fuel and to generate hot combustor exhaust gas

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

The outer combustor liner further defines a cooling air flow path configured to direct a second portion of the compressed air around the outer combustor liner to cool the combustor liner

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP4647663A1Super compact combustor
Publication Date: 2025.11.12 RTX CORP
  • EP4647663A1 patent drawingFigure 1
  • EP4647663A1 patent drawingFigure 2A
  • EP4647663A1 patent drawingFigure 2B

AI summary

A gas turbine engine (100a) include a compressor, a combustor (104) positioned fluidically and physically downstream of the compressor (102), a turbine (108) positioned 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) and also includes a toroidal recirculation zone configured to receive and combust fuel in a rich combustion zone (104a), an ignitor (118) 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 (124).