Diffuser Structures for Combustor Liner Panel Cooling
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Solution Overview
Problem
In gas turbine engines, disruptions or gaps in the cooling airflow within the combustor section can lead to higher localized temperatures on liner panels, causing premature degradation and efficiency loss due to the recirculation of hot combustion gases.
Innovation Solution
The implementation of diffuser structures with specific angles and configurations to direct cooling airflow into gaps between liner panels, increasing the static pressure and preventing the entrainment of hot combustion gases, thereby maintaining liner panel temperatures within safe ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling airflow is provided across the liner panel surface, then liner panel temperatures are reduced, but low pressure vortex forms in the gap between adjacent liner panels causing hot gas recirculation
Solution Approach 1:
A diffuser structure is introduced as an intermediary component between the cooling air source and the gap between liner panels. The diffuser includes a metering portion and a diffuser portion that conditions the cooling airflow before it enters the gap, transforming the flow characteristics to prevent vortex formation while maintaining cooling effectiveness.
Solution Approach 2:
The diffuser structure changes the parameters of the cooling airflow, specifically increasing static pressure and reducing velocity. The metering portion controls the flow rate while the diffuser portion with its expansion angle increases static pressure, transforming the cooling air into a flow that can effectively counteract hot gas recirculation without creating low pressure vortex.
2Temperature
If cooling airflow velocity is increased to improve cooling effectiveness, then liner panel temperatures are reduced, but low pressure vortex forms causing hot gas entrainment
Solution Approach 1:
The diffuser structure transforms the cooling airflow parameters by reducing velocity and increasing static pressure through its expansion geometry. The diffuser portion with expansion angle between 5-45 degrees converts kinetic energy into pressure energy, creating a stable, high-pressure cooling flow that prevents vortex formation while maintaining effective heat transfer.
Solution Approach 2:
The diffuser acts as an intermediary flow conditioning device that decouples the relationship between cooling air supply and gap flow characteristics. It mediates between the cooling air source and the gap environment, transforming the airflow into a form that provides cooling without creating unstable low pressure conditions.
3Temperature
If the gap between liner panels is reduced to prevent hot gas recirculation, then liner panel temperature uniformity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The diffuser structure serves as an intermediary flow control device that addresses hot gas recirculation through flow conditioning rather than geometric constraints. This approach eliminates the need for tight gap tolerances, reducing manufacturing precision requirements while achieving the same temperature uniformity benefits.
Solution Approach 2:
The invention uses pneumatic principles through the diffuser structure to control the cooling airflow characteristics. By using pressure and flow rate control via the diffuser, the system achieves temperature uniformity through fluid dynamics rather than mechanical gap control, thereby reducing manufacturing precision requirements.
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 solution effectively prevents the recirculation of hot gases, maintaining liner panel temperatures and enhancing combustor efficiency by ensuring consistent cooling airflow and pressure within the combustor section.
Implementation Method 1
The diffuser includes a metering portion and a diffuser portion. The diffuser increases a static pressure of cooling air flowing through the diffuser.
Implementation Method 2
The cooling airflow impinges on the liner panel and also is injected along the surface of the liner panel to provide an insulating film of cooling air.
Implementation Method 3
The cooling airflow impinges on the liner panel and also is injected along the surface of the liner panel to provide an insulating film of cooling air.
Data Source
Figure 1
Figure 2~3
Figure 4~8B
AI summary
A combustor assembly (56) for a turbine engine includes a liner panel (64) defining a portion of an inner surface (68) of a combustor chamber (55), liner panel including an end face (70) transverse the inner surface, and at least one diffuser (84) through the end face. A liner panel and a method are also disclosed.