Gas Turbine Combustor Cross Fire Tube Cooling via Dual Pipe

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Solution Overview

Problem

Gas turbine combustors face challenges in preventing thermal deformation and fire damage of cross fire tube assemblies due to high temperatures, while also addressing uneven combustion air flow which leads to increased nitrogen oxide and unburnt carbon monoxide emissions.

Innovation Solution

The design incorporates a cross fire tube assembly with a dual pipe configuration, including openings and guide plates that allow combustion air to flow upstream and downstream of the inner tube, promoting convective heat transfer and uniform air flow to prevent thermal deformation and enhance combustion efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cooling air is introduced into the cross fire tube assembly to prevent thermal deformation and fire damage, then the cross fire tube assembly is protected from high temperatures, but the temperature of combustion exhaust gases is reduced which hampers flame propagation

Engineering Contradiction:

Improvetemperature of cross fire tube assemblyVSAvoidflame propagation capability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The cross fire tube assembly is divided into an inner tube and an outer tube, creating separate flow paths. The inner tube carries combustion exhaust gases for flame propagation while the outer tube introduces cooling air, segmenting the cooling function from the combustion gas flow path.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Cooling air is introduced at specific locations (outer tube) rather than throughout the entire assembly. The cooling is localized to the outer tube wall surface, while the inner tube maintains high temperature for effective flame propagation.

Inventive Principle:

Principle #3Local quality

2Reliability

If the cross fire tube assembly is designed as a dual pipe configuration with inner and outer tubes, then flame propagation is enabled through the inner tube, but the structure becomes more complex and occupies more space

Engineering Contradiction:

Improveflame propagation capabilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The dual pipe structure serves multiple functions: the inner tube enables flame propagation, the outer tube provides structural protection, and the space between them introduces cooling air. This multi-functional design justifies the increased structural complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The inner tube is nested within the outer tube, creating a compact dual pipe configuration. This nesting arrangement maximizes space utilization while maintaining the protective and cooling functions of the outer tube.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Temperature

If openings are provided in the outer tube for cooling air flow, then convective heat transfer is enhanced for cooling the cross fire tube assembly, but combustion air flow uniformity is disrupted leading to increased emissions

Engineering Contradiction:

Improvecooling efficiencyVSAvoidnitrogen oxide and carbon monoxide emissions

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The openings in the outer tube are strategically positioned and sized to create asymmetric flow patterns that promote turbulent mixing. This asymmetric opening configuration enhances cooling while simultaneously improving combustion air mixing to reduce emissions.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

Multiple openings are distributed around the outer tube perimeter, creating multiple cooling channels that replicate the cooling effect throughout the assembly while maintaining overall flow uniformity.

Inventive Principle:

Principle #26Copying

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

This solution effectively cools the cross fire tube assembly without reducing combustion exhaust gas temperature, preventing thermal deformation and fire damage, while reducing nitrogen oxide and unburnt carbon monoxide emissions by ensuring uniform fuel and air mixing.

Implementation Method 1

The guide plates guide the combustion air into a space inside the outer tube via the opening... promoting convective heat transfer

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

the wall surface of the inner tube being cooled by the combustion air in the outer tube

Methodology Applied

Scientific EffectHeat transfer: Convection

Data Source

PatentUS10508813B2Gas turbine combustor cross fire tube assembly with opening restricting member and guide plates

Publication Date: 2019.12.17 MITSUBISHI POWER LTD

AI summary

A plurality of gas turbine combustors having a cross fire tube assembly that connects adjacent combustors. The combustors include combustion chambers having annular combustion air passages on outer peripheries thereof. The cross fire tube assembly has a dual pipe configuration including an inner tube that connects the combustion chambers of the adjacent combustors and an outer tube that covers therein the inner tube and connects the combustion air passages of the adjacent combustors. The cross fire tube assembly further has openings disposed between the inner tube and the outer tube of outer peripheral partition walls of the combustion air passages that are connected with the outer tube of the cross fire tube assembly centering on the inner tube. The openings allow combustion air to flow in areas upstream and downstream of the inner tube with respect to a flow of the combustion air flowing through the combustion air passages.