Exo-skeleton Tile Structure for Gas Turbine Combustion Rigidity
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Solution Overview
Problem
Existing exo-skeleton tile structures in gas turbines lack sufficient rigidity to resist bending in the circumferential direction and offer limited opportunities for tuning out problematic resonances, compromising component life and vibration mode management.
Innovation Solution
A part-annular tile design with circumferentially extending ribs that inter-engage with adjacent tiles to form a complete annular structure, allowing for thermal expansion while resisting relative bending, and featuring a socket mechanism for radial reaction to enhance stiffness and damping of vibrational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the liner shell wall thickness is reduced to resist thermal gradient stresses, then thermal stress resistance is improved, but resistance to pressure buckling deteriorates
Solution Approach 1:
The exo-skeleton structure is divided into multiple discrete tiles that are distributed around the liner shell. Each tile provides localized structural support, and collectively they form a complete support system that prevents pressure buckling while allowing the liner shell to maintain thin walls for thermal stress resistance
Solution Approach 2:
The system combines the thin liner shell material (optimized for thermal stress resistance) with the exo-skeleton tile structure (optimized for mechanical strength and buckling resistance). This composite approach allows each component to be designed for its primary function without compromising the other
2Stability of the object's composition
If the exo-skeleton tile structure is made more rigid to resist bending in the circumferential direction, then structural rigidity is improved, but adaptability to thermal expansion deteriorates
Solution Approach 1:
The tile structure incorporates joints and connection mechanisms that allow dynamic adjustment. The tiles can move relative to each other to accommodate thermal expansion while maintaining sufficient rigidity to resist bending forces during normal operation
Solution Approach 2:
Different regions of the tile structure have different degrees of rigidity. The tiles provide rigid support where needed to resist bending, while the joints and connection areas are designed with controlled flexibility to accommodate thermal expansion and contraction
3Ease of manufacture
If traditional exo-skeleton tile structure is used, then ease of manufacture is maintained, but resistance to bending about axially-extending edges deteriorates
Solution Approach 1:
The tiles are designed with curved surfaces that follow the cylindrical geometry of the liner shell. This curvature provides inherent structural strength to resist bending forces while maintaining the simple modular tile structure that is easy to manufacture and install
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 solution provides enhanced rigidity to the structure, allows for thinner liner shells with improved thermal cycle fatigue life, and optimizes vibration mode tuning through rib optimization and frictional damping in sliding joints.
Implementation Method 1
the ribs of adjacent tiles are relatively slideable circumferentially, to allow thermal expansion and contraction of the annular structure in use
Implementation Method 2
frictional damping in sliding joints
Data Source
AI summary
It is known to assist cooling of a combustion chamber in a gas turbine by fixing an exo-skeleton tile structure to an inner annular combustion liner shell. To improve structural integrity of the exo-skeleton tile structure, each tile is formed with at least one rib extending circumferentially across the outer surface of the tile. An end of each rib projects beyond one edge of the tile, like tiles being linked at overlapping edges by the inter-engagement of a projecting rib of one tile with the rib of an adjacent tile. The inter-engaging ends of the ribs are relatively slideable circumferentially to allow thermal expansion and contraction of the exo-skeleton structure, but sockets are provided where the ribs engage so as to resist relative bending of the adjacent tiles about their linked edges and impart rigidity to the structure.