Segmented Effusion Cooling Holes for Gas Turbine Combustor Liners
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Solution Overview
Problem
Effusion cooling in gas turbine engines experiences low film effectiveness at upstream sections of the combustor and is often interrupted by major combustor orifices, leading to increased complexity, size, weight, and cost due to the need for cooling augmentation.
Innovation Solution
A combustor effusion cooling mechanism featuring two or more sets of effusion cooling holes with varying tangential angles, including initial, final, and interposed rows, where initial rows are angled at 70-90 degrees, final rows at 0-20 degrees, and interposed rows at intermediate angles, to establish and maintain a cooling film effectively across the combustor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If traditional effusion cooling holes are used in combustor liners, then cooling is provided to extend service life, but film effectiveness is low at upstream sections and cooling film is interrupted by major combustor orifices
Solution Approach 1:
The patent applies local quality by varying the tangential angle of effusion cooling holes according to their axial position. Upstream sections (first plurality of rows) use higher tangential angles (45-90 degrees) to generate stronger cooling films where heat flux is highest, while downstream sections (second plurality of rows) use lower angles (0-45 degrees) where the cooling demand is reduced. This localized optimization ensures effective cooling film coverage throughout the combustor length without interruption by major orifices.
2Reliability
If cooling augmentation is added to upstream sections or downstream of major orifices, then cooling effectiveness is improved, but device complexity, size, weight, and cost increase
Solution Approach 1:
The patent employs parameter changes by systematically varying the tangential angle parameter of effusion cooling holes along the axial direction. The transition from higher angles (45-90 degrees) in upstream rows to lower angles (0-45 degrees) in downstream rows creates a progressive cooling effect that maintains film integrity through major combustor orifices. This continuous parameter variation eliminates the need for discrete cooling augmentation devices, thereby reducing complexity while maintaining reliability.
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 enhances combustor cooling efficiency by maintaining effective cooling film coverage and reducing the need for augmentation, thereby improving performance and reducing complexity and costs.
Implementation Method 1
Effusion cooling involves providing a matrix of relatively small diameter effusion cooling holes through the combustor liners, and into which a flow of cooling air is admitted. The effusion cooling holes are typically angled relative to a surface of the combustor. This angle increases the length of the effusion holes through the liners, which increases the surface area from which the cooling flow removes heat from the liner, and generates a cooling film on the inner wall of the liners.
Data Source
Figure 1
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AI summary
A combustor (124) includes two or more sets of effusion cooling holes (402) that extend through the and outer liners (202, 204). Each set of effusion cooling holes (402) includes one or more initial rows (406) of effusion cooling holes (404), one or more final rows (408) of effusion cooling holes (404) disposed downstream of the one or more initial rows (406), and a plurality of interposed rows (412) of effusion cooling holes (404) disposed between the initial and final rows (406, 408). Each effusion cooling hole (404) is disposed at a tangential angle relative to an axial line. The tangential angle of the effusion cooling holes (404) in each set of effusion cooling holes (402) gradually transitions from a substantially transverse tangential angle in each initial row (406) to a substantially axial tangential angle in each final row (408).