Supercharged Combustor Cooling for Compact Gas Turbine Relight

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Solution Overview

Problem

Existing small gas turbine engine designs face limitations in altitude relight capability, reverse flow designs that decrease energy recovery, large combustor packages due to fuel injection systems relying on pumps and manifolds, and undesirably long combustors due to ignitor positioning.

Innovation Solution

A gas turbine engine design with a centrifugal compressor and turbine, featuring a toroidal recirculation zone, integrated ignitor, and supercharged combustor cooling using a shaft cooling air pump to enhance airflow and cooling efficiency, eliminating the need for separate fuel pumps and promoting compact packaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate fuel pump and manifold system is used for fuel injection, then fuel delivery capability is improved, but device complexity and packaging size increase

Engineering Contradiction:
Improvefuel delivery capabilityVSAvoidfuel injection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fuel injection system is merged with the compressor assembly, where the compressor housing itself serves as the fuel injection manifold and the compressor impeller acts as the fuel injection pump. This integration eliminates separate fuel pump and manifold components, reducing device complexity and packaging size while maintaining fuel delivery capability through the compressor's rotational pumping action and integrated fuel injection ports.

Inventive Principle:
Principle #5Merging (Combining)

2Temperature

If combustor cooling air flow is increased to improve cooling efficiency, then combustor liner temperature is reduced, but energy recovery decreases

Engineering Contradiction:
Improvecombustor liner temperatureVSAvoidenergy recovery
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The system applies local quality by providing concentrated cooling air flow precisely where the combustor liner requires it most, through targeted cooling ports and passages in the compressor housing. This localized cooling approach reduces combustor liner temperature in critical areas without requiring excessive overall cooling air flow, thereby minimizing the impact on energy recovery while maintaining effective thermal management.

Inventive Principle:
Principle #3Local quality

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 operability, flame stability, and extended operational life with enhanced energy recovery and compact size, suitable for high-altitude relight capabilities and efficient combustor durability.

Implementation Method 1

A shaft cooling air pump is configured to provide suction to pull the second portion of compressed air through a plurality of hollow 1st stage turbine vanes positioned between the combustor and the turbine and into a turbine air plenum, and to further compress the second portion of the compressed air in the turbine air plenum before the second portion of the compressed air enters the combustor as fuel injector air and combustor secondary inlet air

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

A cooling air flow path is configured to direct a second portion of the compressed air around the outer combustor liner to cool the combustor liner

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

A turbine, which includes a turbine wheel, is positioned fluidically and physically downstream of the combustor and is fluidically connected to the compressor to receive the hot combustor exhaust gas

Methodology Applied
Scientific EffectHeat Engine: Heat Engine

Implementation Method 4

a compressor configured to receive inlet air at a compressor inlet and generate compressed air at a compressor exit

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 5

The shaft is configured to transmit rotational energy from the turbine to the compressor to power the compressor

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP4647666A1Supercharged combustor cooling using turbomachinery
Publication Date: 2025.11.12 RTX CORP
  • EP4647666A1 patent drawingFigure 1
  • EP4647666A1 patent drawingFigure 2A
  • EP4647666A1 patent drawingFigure 2B

AI summary

A gas turbine engine (100a) includes a compressor (102), a combustor (104) downstream of the compressor (102), a turbine (108) 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 as combustor primary inlet air (130a). The combustor (104) includes a combustor liner (140) having an inner combustor liner (140a) and an outer combustor liner (140b), surrounding one or more combustion zones. A cooling air flow path (124) is configured to direct a second portion (130b) of the compressed air around the outer combustor liner (140b) to cool the combustor liner (140) and to provide a source of quench air (130d; 130h), inner combustor liner cooling air (130g), fuel injector air (130i; 130j), and combustor secondary inlet air (130k).