Combustion Liner Turbulator Geometry for Cooling With Low Pressure Loss

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Solution Overview

Problem

Existing combustion liners in gas turbine engines face challenges in effectively managing high temperatures, with thermal barrier coatings and passive cooling methods often insufficient to prevent melting and erosion, leading to potential damage.

Innovation Solution

The implementation of turbulators with specific ramp angles and dimensions on the outer surface of combustion liners to enhance active cooling, combined with a redesigned cross fire tube retention system that minimizes airflow obstruction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermal barrier coating is applied to the combustion liner, then the combustion liner temperature is reduced, but the coating alone is insufficient to prevent melting and erosion

Engineering Contradiction:
Improvecombustion liner temperatureVSAvoidprotection from melting and erosion
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent combines thermal barrier coating with active cooling system (cooling holes) to create a composite protection system. The thermal barrier coating provides thermal insulation while the active cooling system supplies cooler air to maintain structural integrity, together providing comprehensive protection against melting and erosion that neither component could achieve alone.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces cooling air as an intermediary substance that flows through cooling holes to transfer heat away from the combustion liner. This intermediary cooling air acts as a heat sink, absorbing excess thermal energy and transporting it away from critical areas, thereby enhancing the protective effect of the thermal barrier coating.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If cooling holes are incorporated for active cooling, then the combustion liner is better protected, but the system complexity increases

Engineering Contradiction:
Improveprotection from hot combustion gasesVSAvoidcooling system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The combustion liner incorporates cooling holes that create a porous structure, allowing cooling air to permeate through the liner wall. This porous design enables active cooling functionality while maintaining structural integrity, providing a relatively simple implementation of active cooling compared to more complex multi-layered cooling systems.

Inventive Principle:
Principle #31Porous materials

3Use of energy by moving object

If turbulators with specific ramp angles are implemented, then heat transfer is enhanced, but the device complexity increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidturbulator geometry
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent applies turbulators with specific ramp angles (first ramp angle on first side, second ramp angle on second side) only to specific portions of the combustion liner where enhanced heat transfer is most needed. This localized application of complex geometry optimizes heat transfer efficiency in critical areas while avoiding unnecessary complexity in other regions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The turbulators feature asymmetric geometry with different ramp angles on opposite sides (first ramp angle vs. second ramp angle). This asymmetric design optimizes heat transfer by creating specific flow patterns and turbulence characteristics that enhance thermal exchange, while the asymmetry itself is a relatively simple geometric modification rather than a complex mechanism.

Inventive Principle:
Principle #4Asymmetry

4Reliability

If conventional retention systems are used for cross fire tubes, then airflow obstruction increases, but the retention function is provided

Engineering Contradiction:
Improvecross fire tube retentionVSAvoidpressure loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts or removes the cross fire tubes from the main airflow path by positioning them in a manner that minimizes obstruction. The retention system is designed to hold the cross fire tubes in positions where they provide necessary retention functionality while creating minimal resistance to the primary airflow, thereby reducing pressure loss.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enhances heat transfer and reduces pressure loss while effectively protecting the combustion liner from high temperatures, improving operational efficiency and reducing emissions.

Implementation Method 1

cooling air can pass along an outer surface of the combustion liner in order to cool a backside of the combustion liner

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

enhances heat transfer and reduces pressure loss while effectively protecting the combustion liner from high temperatures

Methodology Applied
Scientific EffectHeat Conduction: Conduction (thermal)

Implementation Method 3

the combustion liner is typically covered with a protective thermal barrier coating on the surface of the liner in direct contact with the hot combustion gases

Methodology Applied
Scientific EffectThermal Insulation: Thermal Insulation

Implementation Method 4

Active cooling can be incorporated in the form of cooling holes, where air cooler than the hot combustion gases passes therethrough to cool the wall of the combustion liner

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3874204B1Turbulator geometry for a combustion liner
Publication Date: 2025.12.10 CHROMALLOY GAS TURBINE LLC
  • EP3874204B1 patent drawingFigure 1
  • EP3874204B1 patent drawingFigure 2
  • EP3874204B1 patent drawingFigure 3~4

AI summary

A heat transfer mechanism is provided comprising a plurality of turbulators located along a surface of a body, such as a combustion liner. The turbulators have a first side with a first ramp angle, a second side with a second ramp angle, a height, and a base width, where the base width is a function of the height and where the turbulators are spaced an axial distance apart that is a function of the turbulator height.