Bulk Swirl Quench Combustor Layout for Compact 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, enhancing flame stability and operability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a conventional fuel injection system is used, then fuel can be delivered to the combustor, but the system requires a larger package size and higher complexity

Engineering Contradiction:
Improvefuel injection system complexityVSAvoidfuel distribution efficiency
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The fuel pump function is extracted from a separate mechanical component and integrated into the rotating shaft itself. The shaft now contains internal fuel passages and pumping elements that deliver fuel directly to the combustor, eliminating the need for an external fuel pump and reducing overall system complexity while maintaining effective fuel distribution

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The shaft is designed to perform multiple functions simultaneously: it transmits rotational energy from turbine to compressor, provides structural support, serves as a fuel delivery system with internal passages, and acts as a cooling air pump. This multi-functionality reduces the number of separate components needed in the system

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

2Temperature

If combustor inlet air is used for cooling exhaust gases, then cooling is achieved, but reverse flow occurs and altitude relight capability deteriorates

Engineering Contradiction:
Improveexhaust gas coolingVSAvoidaltitude relight capability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The cooling air supply is segmented into separate sources: dedicated shaft cooling air passages provide cooling to the exhaust gases without creating reverse flow, while the combustor inlet air remains dedicated to combustion and relight functions. This segmentation allows independent optimization of cooling and relight capabilities

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shaft cooling air passages act as an intermediary system that provides the necessary cooling function without directly involving the combustor inlet air flow. This intermediary cooling path prevents the adverse interaction between cooling and relight functions that occurs in conventional designs

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If ignitor is positioned for optimal combustion, then flame stability is achieved, but combustor length increases

Engineering Contradiction:
Improveflame stabilityVSAvoidcombustor length
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The ignitor is repositioned from a downstream location to an upstream position within the toroidal recirculation zone. This spatial reconfiguration in a different dimension of the combustor allows the ignitor to effectively ignite and stabilize flames without extending the overall combustor length, as the recirculation zone provides a compact volume for flame establishment

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Volume of moving object

If additive manufacturing is used for combustor construction, then compact size and design flexibility are achieved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecombustor sizeVSAvoidadditive manufacturing precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

Multiple combustor components (combustor liner, toroidal recirculation zone, quench zone, lean combustion zone, and ignitor housing) are merged into a single integrated structure manufactured in one additive manufacturing process. This consolidation achieves compact size and design flexibility while distributing precision requirements across the entire manufactured part rather than requiring high-precision assembly of multiple separate components

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 size, and enhanced operational life with efficient fuel distribution and cooling, supporting high-energy exhaust for turbine recovery.

Implementation Method 1

a toroidal recirculation zone configured to receive and combust fuel

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

The rapid quench zone is configured to receive and quench with quench air combustion products from the rich combustion zone

Methodology Applied
Scientific EffectHeat transfer: Convection

Implementation Method 3

direct a second portion of the compressed air around an outer combustor liner to cool the combustor liner

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

A shaft cooling air pump is configured to further compress the second portion of the compressed air before the second portion of the compressed air enters the combustor

Methodology Applied
Scientific EffectMechanical compression: Compression

Data Source

PatentEP4647661A1Rapid bulk swirl quench zone for super compact combustor
Publication Date: 2025.11.12 RTX CORP
  • EP4647661A1 patent drawingFigure 1
  • EP4647661A1 patent drawingFigure 2A
  • EP4647661A1 patent drawingFigure 2B

AI summary

A gas turbine engine (100a) includes a compressor (102) configured to receive inlet air at a compressor inlet (102a) and generate compressed air (130) 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) 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) configured to direct a second portion (130b) of the compressed air (130) around an outer combustor liner (140).