Reinforced Gas Turbine Combustor Floatwall for Dirt-Resistant Cooling
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Solution Overview
Problem
Gas turbine engine combustors face challenges with excessive heat loads leading to oxidation, cracking, and thermal stresses, as well as accumulation of foreign matter in cooling cavities, necessitating improved cooling characteristics and reduced susceptibility to dirt accumulation.
Innovation Solution
A dual-walled structure with shingled heat shield panels and cooling pins, featuring forward and rearward rails, apertures, and effusion holes, enhances cooling efficiency and minimizes dirt deposition, using materials like nickel, aluminum, titanium, steel, and ceramic matrix composites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a dual wall structure with cooling cavities is used, then cooling efficiency is improved, but foreign matter accumulation increases
Solution Approach 1:
The heat shield panels incorporate effusion holes (porous structure) that allow cooling gas to pass through and form a protective film on the combustor liner surface. This porous design enables cooling while preventing foreign matter accumulation by maintaining a gas barrier between the cooling cavity and the external environment.
Solution Approach 2:
The heat shield is divided into multiple discrete panels with gaps between them. This segmentation allows the cooling gas to escape through the gaps and form a film cooling layer, while also preventing foreign matter from accumulating in the cooling cavities by maintaining an open pathway for gas flow.
2Temperature
If heat shield panels are positioned close to combustor liner, then cooling effectiveness increases, but dirt accumulation in gaps increases
Solution Approach 1:
The heat shield panels are designed to be movable relative to the combustor liner, allowing dynamic adjustment of the gap size. During operation, the panels can be positioned to optimize cooling effectiveness while preventing dirt accumulation by maintaining adequate spacing that allows gas flow but prevents particle ingress.
Solution Approach 2:
The gaps between heat shield panels and the combustor liner are designed with specific local characteristics - narrow enough to provide effective cooling film formation, but with sufficient spacing and orientation to prevent foreign matter accumulation. The gap geometry is optimized locally at different positions around the combustor.
3Temperature
If cooling gas flow rate is increased, then film cooling quality improves, but gas consumption increases
Solution Approach 1:
The effusion holes provide distributed gas injection across the heat shield surface, creating an efficient film cooling layer. This porous injection method achieves high cooling quality with lower gas consumption compared to concentrated injection, as the cooling gas is distributed optimally across the surface.
Solution Approach 2:
The cooling system uses partial action by injecting cooling gas only where needed through the effusion holes and gaps, rather than cooling the entire surface uniformly. This targeted approach improves film cooling quality at critical locations while reducing overall gas consumption.
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 robust film cooling, reduces thermal stress, and minimizes foreign matter accumulation, thereby protecting the combustor structure from excessive temperatures and improving durability.
Implementation Method 1
a plurality of cooling pins extending upwardly and away from the outer surface towards a surface of the at least one combustor liner
Implementation Method 2
the panel portion also includes a plurality of apertures extending from the outer surface to the inner surface
Data Source
AI summary
An assembly for a combustor for a gas turbine engine, including: a plurality of heat shield panels attached to at least one combustor liner, each one of the plurality of heat shield panels including a panel portion and a first forward rail and a second rearward rail each extending from an outer surface of the panel portion, the panel portion including an inner surface opposite of the outer surface, the panel portion also includes a forward end and a rearward end, the forward end of the panel portion is axially forward of the rearward end of an adjacent heat shield panel of the plurality of heat shield panels such that a gap is defined between the outer surface of the panel portion of one heat shield panel of the plurality of heat shield panels and an inner surface of the panel portion of an adjacent heat shield panel of the plurality of heat shield panels, the panel portion also includes a plurality of apertures extending from the outer surface to the inner surface; and a plurality of cooling pins extending upwardly and away from the outer surface towards a surface of the at least one combustor liner.