Gas Turbine Combustor Liner with Internal Threads
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Solution Overview
Problem
The existing combustor wall designs for gas turbines face challenges in maintaining effusion hole integrity due to thermal barrier coating application, leading to blockages and reduced convective heat removal, and the attachment studs obstruct cleaning jets, complicating the manufacturing process and increasing production costs.
Innovation Solution
A liner element with integrally formed and internally threaded protuberances spaced from the cooling side surface, allowing for efficient affixing to the structural wall and reducing the obstruction for cleaning jets, enabling effective cleaning of effusion holes and improving manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If externally threaded studs are used to attach the tile to the combustor wall, then the tile can be securely affixed, but the studs obstruct cleaning jets and complicate the manufacturing process
Solution Approach 1:
The invention extracts the threading function from the external studs and relocates it to internal threads within recesses of the tile. This allows the studs to be shorter and not protrude as much, eliminating the obstruction problem for cleaning jets while maintaining secure attachment capability.
Solution Approach 2:
Instead of having external threaded studs protruding from the tile surface, the invention inverts the configuration by providing internally threaded recesses in the tile that receive unthreaded studs. This inversion eliminates the obstruction issue while preserving the attachment function.
2Productivity
If laser cutting is used to form effusion holes through thermal barrier coating, then holes can be formed efficiently, but reduced laser power is required which increases cycle time and production cost
Solution Approach 1:
The effusion holes are formed through the thermal barrier coating before the coating is applied to the tile. This preliminary action allows full-power laser cutting without the constraint of protecting the coating, significantly reducing cycle time and production cost while maintaining hole integrity.
3Productivity
If effusion holes are formed through thermal barrier coating, then cooling function is provided, but the coating can crack and delaminate leading to premature coating loss
Solution Approach 1:
The effusion holes are formed through the thermal barrier coating before the coating is applied to the tile. This preliminary action eliminates the mechanical stress of laser cutting through the coating, preventing cracking and delamination while maintaining the cooling function.
Solution Approach 2:
The invention converts the potential harm of laser cutting damaging the coating into a benefit by performing the cutting before coating application. The locations where holes will be needed are pre-marked, and the coating is applied over these marked locations, ensuring holes are formed through the coating without causing damage.
4Ease of operation
If shorter internally threaded protuberances are used, then cleaning jet obstruction is reduced, but attachment reliability may be compromised
Solution Approach 1:
The threading function is extracted from the protruding studs and moved into recesses of the tile. This allows the use of shorter stud-like protuberances that do not obstruct cleaning jets, while the internal threads provide sufficient engagement area to maintain attachment reliability.
Solution Approach 2:
The attachment mechanism transitions from external protruding studs to internal recessed threads, changing the dimensional arrangement. This allows the attachment function to be maintained while reducing the protrusion height that obstructs cleaning operations.
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 design ensures effective cleaning of effusion holes, maintains thermal barrier coating integrity, and enhances manufacturing efficiency by allowing for a closer nozzle approach and reduced production costs through improved thread quality and increased production capacity in vertically stacked arrays.
Implementation Method 1
The outer wall is provided with a number of feed holes through which cooling air drawn from the engine's compressor is directed so as to pass into the chambers defined between each inner tile and the outer wall, for impingement on the aforementioned cooling side surface of the inner tile, thereby providing impingement cooling to the inner tile
Implementation Method 2
The inner tiles are each furthermore provided with a plurality of so-called effusion holes which define flow passages through the tiles from their cooling side surfaces to oppositely directed combustion side surfaces which face the interior of the combustor where combustion will take place during operation of the engine. The cooling air which is directed into the chambers and which impinges on the cooling side surface of the tiles is thus exhausted through the effusion holes and in doing so provides convective heat removal from the tiles
Implementation Method 3
The air subsequently forms a thin film of air over the tiles' combustion side surfaces which helps to protect the tiles from the combustion flame inside the combustor
Data Source
AI summary
There is disclosed a liner element in the form of an impingement/effusion tile for a gas turbine combustor having a structural wall. The liner element has a unitary construction defining a cooling side and combustion side, and a plurality of effusion holes extending between a cooling side surface of the element and a combustion side surface of the element. The liner element is configured to be affixed to the structural wall of a combustor with its cooling side surface spaced from the structural wall to define a chamber between the cooling side surface and the structural wall, and the liner element further includes integrally formed and internally threaded protuberances on its cooling side, the protuberances being arranged to engage the structural wall.