Gas Turbine Combustor Effusion Cooling Angles
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Solution Overview
Problem
Effusion cooling in gas turbine engine combustors has low film effectiveness at upstream sections and is often interrupted by dilution holes, requiring additional cooling augmentation, which complicates construction and increases size, weight, and cost.
Innovation Solution
A dual wall combustor design with an inner and outer liner, featuring impingement cooling holes in the cold wall and effusion cooling holes in the hot wall, arranged in multiple rows with varying tangential angles to enhance cooling air flow and maintain effective cooling across all sections without additional augmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If effusion cooling holes are used in the combustor liner, then cooling is provided for the high temperature combustor, but film effectiveness is low at upstream sections and cooling is interrupted by dilution holes
Solution Approach 1:
The effusion cooling holes are divided into multiple rows with different orientations. The first row has holes oriented at a first angle (e.g., 45 degrees) to the axial direction, while the second row has holes oriented at a second angle (e.g., 90 degrees) to the axial direction. This segmentation allows different sections of the liner to receive cooling optimized for their specific thermal and flow conditions, maintaining consistent film effectiveness throughout the combustor despite the presence of dilution holes.
2Reliability
If cooling augmentation is added to improve film effectiveness, then cooling performance improves, but construction complexity and size increase
Solution Approach 1:
The effusion cooling holes serve multiple functions: they provide cooling film formation, they compensate for cooling interruptions caused by dilution holes, and they adapt to different thermal conditions along the combustor length through their varied orientations. This multi-functionality eliminates the need for separate cooling augmentation devices, maintaining film effectiveness while avoiding increased construction complexity.
3Temperature
If effusion cooling holes are angled to generate cooling film, then cooling film is formed on the inner wall, but the liner length increases
Solution Approach 1:
The orientation angles of the effusion cooling holes are optimized to achieve the desired cooling film formation with minimal liner length increase. By carefully selecting the angles (first angle for upstream sections, second angle for downstream sections), the cooling effectiveness is maximized while the additional length required is minimized, achieving a balance between thermal protection and compact design.
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 dual wall combustor configuration improves film effectiveness and maintains efficient cooling throughout the combustor, reducing thermal stress and strain without the need for additional cooling augmentation, thus enhancing the overall cooling efficiency and durability.
Implementation Method 1
a plurality of impingement cooling holes arranged in the cold wall of the outer liner allowing cooling air to flow through the cold wall to the hot wall
Implementation Method 2
a plurality of rows of effusion cooling holes disposed in the hot wall and configured to direct at least a portion of the cooling air through the hot wall onto an inner surface of the hot wall
Data Source
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AI summary
A gas turbine engine combustor is provided. An inner liner has an upstream end and a downstream end and extends in an axial direction between the upstream and downstream ends. A dual wall outer liner has a hot wall, a cold wall at least partially surrounding the hot wall, an upstream end, and a downstream end. The outer liner extends in the axial direction between the upstream (224) and downstream (226) ends. A dome assembly is coupled between the upstream ends of the inner and outer liners to define a combustion chamber between the inner liner and the hot wall of the outer liner. Effusion cooling holes (304) are disposed in the hot wall (216), including a first row (306) disposed at a tangential angle of between about 70° and about 90° and a second row (308) disposed at a tangential angle of between about 0° and about 20°.