Segmented Trapped Vortex Cavity for Afterburner Thermal Stress
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Solution Overview
Problem
Trapped vortex cavity flame stabilizers in afterburners face challenges with thermal stress and cooling due to high temperature gradients, and existing designs are difficult to manufacture and repair, particularly with the need for thousands of small cooling holes in a one-piece ring structure.
Innovation Solution
An annular segmented trapped vortex cavity assembly with expandable joints and subcomponents allows for easier manufacturing and repair, featuring air injection holes and cooling slots to reduce thermal stress, and the ability to weld subcomponents for improved durability and reduced thermal barrier coating requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a one-piece ring trapped vortex cavity structure is used, then the structural integrity and flame stabilization performance are improved, but the manufacturing complexity and thermal stress resistance deteriorate due to the need for thousands of cooling holes and thermal barrier coatings
Solution Approach 1:
The one-piece ring trapped vortex cavity is divided into multiple segmented blocks that can be manufactured separately and then assembled. Each block can be independently cooled and coated, eliminating the need to drill thousands of holes through a single large ring structure. The segments are joined using expansion joints and bonding techniques to maintain structural integrity while improving manufacturability.
2Strength
If a one-piece ring trapped vortex cavity structure is used, then the structural integrity is improved, but the ease of repair deteriorates when thermal distress or damage occurs
Solution Approach 1:
By dividing the cavity into replaceable segments, individual damaged blocks can be removed and replaced without affecting the entire structure. This modular approach allows for targeted repair of only the affected segments, significantly reducing repair time and complexity compared to repairing or replacing a monolithic one-piece ring.
3Reliability
If thermal barrier coating is applied to the one-piece ring structure, then the thermal stress resistance is improved, but the coating application complexity increases due to the physical size of spray nozzles relative to cavity dimensions
Solution Approach 1:
Segmenting the cavity into smaller blocks provides accessible surfaces that can be easily coated with thermal barrier materials using conventional spray techniques. Each segment's external surfaces are more readily accessible to coating equipment, eliminating the difficulty of applying coatings to the internal cavities of a large one-piece ring structure.
4Temperature
If cooling holes are drilled in a one-piece ring structure, then the thermal management is improved, but the manufacturing precision and structural integrity deteriorate due to the large number of holes required
Solution Approach 1:
Each segmented block requires far fewer cooling holes than a one-piece ring structure, making the drilling process more manageable and precise. The reduced number of holes per segment decreases the cumulative manufacturing error and maintains structural integrity while still providing adequate cooling pathways.
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 segmented design enhances performance by reducing thermal and structural stresses, simplifying manufacturing, and providing effective cooling, thereby improving the durability and reliability of the afterburner while maintaining high temperature resistance.
Implementation Method 1
first and second expansion joint features at distal first and second ends separated by a center section of the annular trapped vortex cavity assembly segment
Implementation Method 2
Radially spaced apart pluralities of air injection first and second holes are disposed through the cavity forward and aft walls respectively
Data Source
AI summary
An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall therebetween defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.