Segmented Cooling Shroud for Combustor Liner Vibration

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Solution Overview

Problem

The existing designs of cooling shrouds in gas turbines face challenges in accommodating thermal expansion and reducing vibrations, which can lead to reduced part life and shorter maintenance intervals.

Innovation Solution

The design incorporates an inner cooling shroud with segmented circumferential segments, where the distance between segments is greater at the forward end than at the aft end, and a distributed fastening system with staggered rows to minimize vibrations and accommodate thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a cooling shroud is used to cool the inner liner shell, then the thermal management is improved, but the thermal expansion and vibrations increase, reducing part life

Engineering Contradiction:

Improvethermal managementVSAvoidpart life

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The cooling shroud is divided into multiple circumferential segments that can expand and vibrate independently. This segmentation allows each segment to accommodate thermal expansion and reduce vibration stresses, thereby maintaining part life while effectively cooling the inner liner shell

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The forward end of the cooling shroud is designed with a greater distance from the inner liner shell compared to the aft end. This non-uniform spacing creates local flexibility at the forward end to accommodate thermal expansion and vibration, while maintaining effective cooling contact at the aft end

Inventive Principle:

Principle #3Local quality

2Temperature

If the cooling shroud is positioned close to the inner liner shell for effective cooling, then cooling efficiency is improved, but thermal expansion accommodation is reduced

Engineering Contradiction:

Improvecooling efficiencyVSAvoidthermal expansion accommodation

Core Design Contradiction:

TemperatureVSAdaptability or versatility

Solution Approach 1:

The cooling shroud is segmented circumferentially, allowing each segment to move independently to accommodate thermal expansion while maintaining close proximity for effective cooling

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cooling shroud has non-uniform spacing with greater distance at the forward end and smaller distance at the aft end, providing local flexibility for thermal expansion while maintaining effective cooling where needed

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the cooling shroud is made as a single piece for simplicity, then manufacturing is easier, but vibration reduction and thermal expansion accommodation are worsened

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidvibration reduction

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The cooling shroud is divided into multiple circumferential segments that can vibrate independently, reducing overall vibration and stress on the structure. The segments are joined in a manner that maintains structural integrity while allowing relative movement

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The segmented design allows the cooling shroud to dynamically adapt to thermal expansion and vibration conditions, with each segment able to move independently to accommodate changing operational conditions

Inventive Principle:

Principle #15Dynamics

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 configuration effectively reduces vibrations and allows for thermal expansion, enhancing the durability and maintenance intervals of the combustor components.

Implementation Method 1

Air 2 flows along the liner shells 23, 33 of the combustor 100 in a cooling air flow direction opposite to the direction of the hot gas flow 26 within the combustion zone 15 and the transition zone 25, the air 2 thereby convectively cooling the liner shells 23, 33

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

The distance between the cooling shroud segments and the inner liner shell is greater at the forward end than at the aft end. A plurality of distributed fastening elements, which fastens the cooling shroud segments on the inner liner shell, is distributed across an axial length of the cooling shroud segments in circumferentially staggered rows

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10697634B2Inner cooling shroud for transition zone of annular combustor liner

Publication Date: 2020.06.30 GE INFRASTRUCTURE TECH LLC

AI summary

An annular combustor includes an inner liner shell and an outer liner shell defining an interior volume through which combustion gases flow in a gas flow direction from a forward end to an aft end. A cooling shroud is attached radially outward of the inner liner shell, forming a cooling passage between the inner liner shell and the cooling shroud. The cooling passage directs air in an air flow direction opposite to the gas flow direction. The cooling shroud is assembled from circumferentially adjoined cooling shroud segments, and the distance between the cooling shroud segments and the inner liner shell is greater at the forward end than at the aft end. Fastening elements are distributed across an axial length of the cooling shroud segments in circumferentially staggered rows. Each forwardmost fastening element is disposed immediately adjacent to a curved portion at the forward end of each respective cooling shroud segment to reduce vibration.