Combustor Heat Shield Edge Cooling via Turbulent Perimeter Paths
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Solution Overview
Problem
In gas turbine engines, excessive leakage of cooling air over the edges of heat shield panels leads to energy loss and reduced efficiency, as conventional cooling methods are inefficient and wasteful.
Innovation Solution
A combustor heat shield design featuring a rail-less contour with a perimeter band of turbulators that create tortuous cooling paths and effusion holes, which control airflow and enhance heat transfer, reducing air leakage and improving cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional cooling methods are used for heat shield panels, then cooling is provided, but excessive cooling air leakage occurs leading to energy loss and reduced efficiency
Solution Approach 1:
The patent applies different cooling mechanisms to different regions of the heat shield panel. The perimeter band with tortuous paths is applied specifically at the edges where leakage occurs, while the central area uses effusion holes for uniform cooling. This localized approach reduces energy loss at critical leakage points without compromising overall cooling efficiency.
Solution Approach 2:
The tortuous paths create curved, serpentine flow channels through the perimeter band instead of straight paths. This curvature increases the flow path length and turbulence, enhancing heat transfer at the edges while controlling air leakage more effectively than conventional straight-path cooling methods.
2Temperature
If cooling air is increased to improve heat shield cooling, then cooling performance improves, but combustion efficiency decreases and emissions increase
Solution Approach 1:
The patent changes the flow path parameters by introducing tortuous paths with increased length and complexity in the perimeter band. This modifies the cooling air flow characteristics to enhance heat transfer coefficients at the edges, achieving effective cooling at lower overall air flow rates, thus preserving combustion efficiency.
Solution Approach 2:
By concentrating enhanced cooling features (tortuous paths) only at the perimeter band where heat transfer needs are highest, the patent achieves effective heat shield temperature control without requiring excessive cooling air, thereby maintaining combustion efficiency and reducing emissions.
3Device complexity
If cooling air leakage at heat shield edges is not controlled, then simple cooling structure is maintained, but energy is wasted and engine efficiency is reduced
Solution Approach 1:
The cooling structure is segmented into two distinct functional zones: a perimeter band with tortuous paths for edge cooling and leakage control, and a central area with effusion holes for uniform cooling. This segmentation allows targeted control of cooling air at the leakage-prone edges without significantly increasing overall structural complexity.
Solution Approach 2:
The tortuous paths introduce curved flow channels within the perimeter band, creating a more complex local structure that controls edge leakage effectively. However, this localized complexity is confined to the perimeter region and does not substantially increase the overall device complexity while significantly reducing energy waste.
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 effectively minimizes air leakage and enhances heat transfer at the edges of the heat shield, improving cooling efficiency and reducing energy consumption, while maintaining robustness and aerodynamic performance.
Implementation Method 1
turbulators defining tortuous cooling paths across the perimeter band
Implementation Method 2
enhances heat transfer at the edges of the heat shield
Implementation Method 3
effusion holes distributed over the central area
Data Source
AI summary
A combustor heat shield comprises a panel body having a front surface and a back surface. The back surface has rail-less edges and a turbulator band extending inwardly from the rail-less edges. The band includes a plurality of turbulators defining tortuous cooling paths up to the rail-less edges. Effusion holes are distributed over the central area.