Turbulator Geometry for Combustion Liner Cooling
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Solution Overview
Problem
Current heat transfer mechanisms in gas turbine engines, such as thermal barrier coatings and passive cooling methods, are insufficient to effectively manage the high temperatures encountered by combustion liners, which can lead to melting and erosion.
Innovation Solution
The implementation of a turbulator configuration on the outer surface of a combustion liner, featuring a plurality of turbulators with specific ramp angles, heights, and base widths, designed to enhance heat transfer by increasing the surface area and airflow interaction, thereby actively cooling the liner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal barrier coating is applied to the combustion liner, then the liner temperature is reduced by approximately 160 deg. F., but the coating alone is not sufficient to prevent melting and erosion from hot combustion gases
Solution Approach 1:
The patent applies different surface characteristics to different regions of the combustion liner. Turbulators are positioned specifically in regions where cooling is most needed, creating localized variations in heat transfer characteristics. This allows the thermal barrier coating to work in conjunction with enhanced cooling zones rather than requiring uniform over-engineering throughout the entire liner.
Solution Approach 2:
The solution combines multiple protective mechanisms: thermal barrier coating material combined with turbulator-induced active cooling. This composite approach layers different protective functions (thermal insulation from coating + convective cooling from turbulators) to achieve reliable protection that neither method could provide alone.
2Reliability
If active cooling with cooling holes is implemented, then the combustion liner is protected from hot gases, but the system complexity increases and additional cooling air is required
Solution Approach 1:
The patent extracts the cooling function from the traditional cooling hole approach and implements it through surface-mounted turbulators. This removes the need for penetrating cooling holes through the liner wall, simplifying the structural design while maintaining active cooling capability. The cooling function is achieved through external airflow manipulation rather than internal hole networks.
Solution Approach 2:
The turbulators serve as an intermediary element between the hot combustion gases and the liner surface. Rather than directly introducing cooling air through holes, the turbulators mediate the heat transfer process by enhancing convective cooling through controlled airflow patterns over the liner surface.
3Temperature
If cooling air is passed along the outer surface of the combustion liner, then backside cooling is achieved, but the airflow distribution and cooling efficiency need optimization
Solution Approach 1:
The turbulator configuration creates dynamic airflow patterns that adapt to the combustion environment. The raised edges and specific geometries cause the cooling air to follow optimized flow paths along the liner surface, dynamically adjusting the cooling distribution to match thermal loading patterns rather than using static, uniform cooling.
Solution Approach 2:
The patent optimizes cooling efficiency by carefully controlling geometric parameters of the turbulators (height, spacing, shape) and airflow parameters (velocity, distribution). These parameter optimizations maximize heat transfer coefficients and ensure efficient cooling of the liner backside without requiring excessive cooling air flow rates.
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 significantly reduces the temperature of the combustion liner by enhancing heat transfer, minimizing the risk of melting and erosion, and optimizing airflow to maintain efficient engine operation.
Implementation Method 1
A plurality of turbulators are located along an outer surface of the first cylindrical portion and the conical portion... designed to enhance heat transfer by increasing the surface area and airflow interaction, thereby actively cooling the liner
Implementation Method 2
The plurality of turbulators are provided to enhance the heat transfer along a surface subject to high temperature loads
Data Source
AI summary
A heat transfer mechanism is provided comprising a plurality of turbulators located along a surface of a body, such as a combustion liner. The turbulators have a first side with a first ramp angle, a second side with a second ramp angle, a height, and a base width, where the base width is a function of the height and where the turbulators are spaced an axial distance apart that is a function of the turbulator height.