Core Ventilation Suction Cooling for Post-Shutdown Combustor Coking

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Solution Overview

Problem

During gas turbine engine shutdown, residual heat causes temperature increases leading to carbon deposits (coking) in fuel nozzles, fuel tubes, and oil tubes, resulting in costly issues like engine start problems and inefficient combustion.

Innovation Solution

A suction enabled post shutdown combustor cooling and ventilation system that draws air from the core flow path and combustor cavity, promoting airflow to dump hot air to the open environment, reducing coking risk in fuel nozzles and fuel manifolds by using pumps, valves, and blower systems to manage airflow during shutdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If cooling systems are shut down during engine shutdown, then energy consumption is reduced, but temperature increases causing carbon deposits in fuel components

Engineering Contradiction:

Improveenergy consumptionVSAvoidcarbon deposits

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The system activates cooling airflow before shutdown is complete and maintains it during shutdown to prevent carbon deposit formation. The suction system is engaged in advance to draw cooling air through the combustor and fuel nozzle areas, removing hot gases before they can cause coking.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses the engine's own residual heat and pressure differentials to drive the cooling airflow during shutdown. The hot gases that would normally cause harm are redirected through the suction system to create the driving force for cooling, converting the harmful thermal energy into a beneficial cooling mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If suction system operates during shutdown, then coking is prevented, but device complexity increases

Engineering Contradiction:

Improvecoking preventionVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The suction system is designed to serve multiple functions: it operates during normal engine operation for general ventilation and is repurposed to provide targeted cooling during shutdown. The same pump, valves, and ducting are used for both operational and shutdown cooling, eliminating the need for separate dedicated shutdown cooling components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the engine's own residual pressure and temperature differentials during shutdown to drive the cooling airflow. The suction pump leverages the existing thermal and pressure gradients within the engine to create cooling flow without requiring external power sources or additional complex control systems.

Inventive Principle:

Principle #25Self-service

3Temperature

If cooling airflow is increased, then temperature control is improved, but energy consumption increases

Engineering Contradiction:

Improvetemperature controlVSAvoidenergy consumption

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The suction system operates in periodic cycles during shutdown rather than continuously at full capacity. The system activates cooling airflow when temperature thresholds are approached and reduces or stops when temperatures are within acceptable ranges, creating a periodic on-off operation that maintains temperature control while minimizing energy consumption.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the suction pump speed, valve positions, and airflow rates based on real-time temperature measurements and engine shutdown phase. By changing operational parameters such as pump RPM and valve opening degrees, the system optimizes cooling effectiveness while minimizing energy consumption at different stages of shutdown.

Inventive Principle:

Principle #35Parameter changes

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 system effectively prevents coking in fuel nozzles and fuel/oil tubes, reducing the risk of component failure and ensuring efficient engine operation post-shutdown by ventilating the core flow path and removing residual heat.

Implementation Method 1

A suction enabled post shutdown combustor cooling and ventilation system that draws air from the core flow path and combustor cavity

Methodology Applied

Scientific EffectSuction: Suction

Implementation Method 2

using pumps, valves, and blower systems to manage airflow during shutdown

Methodology Applied

Scientific EffectForced Convection: Forced Convection

Data Source

PatentUS20260063074A1Suction enabled post shutdown combustor cooling and core ventilation

Publication Date: 2026.03.05 RTX CORP

AI summary

A suction enabled post shutdown combustor cooling and ventilation system including a pump fluidly coupled with a suction line, wherein the suction line is fluidly coupled with suction ports proximate a compressor; a pump suction valve positioned in the suction line upstream of the pump; a pump discharge line fluidly coupled with the pump, an outlet fluidly coupled with the pump discharge line; and an engine core flow path fluidly coupled with the suction ports.