Combustion Chamber Orifice Geometry for Stress-Adapted Cooling
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Solution Overview
Problem
Existing combustion chamber designs suffer from stress concentration at orifice edges due to non-uniform mechanical stresses, leading to cracks and fissures, and create aerodynamic disturbances with non-homogeneous airflow orientations.
Innovation Solution
Adapt the cross-section of each orifice's external end to align with the mechanical stresses during operation by using tools with variable cross-sections, such as laser beams or water jets, to perforate the combustion chamber walls along specific axes, ensuring uniform airflow and reducing stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If openings are made with a circular cross-section tool inclined at an angle, then cooling air injection is achieved, but the external end of each orifice has an elliptical cross-section causing stress concentration at the minor radius
Solution Approach 1:
The patent applies local quality by adapting the cross-section of each orifice's external end to align with the local mechanical stress directions. Instead of using a uniform circular cross-section tool for all orifices, the invention varies the tool cross-section (circular, elliptical, or other shapes) depending on the specific stress conditions at each location on the combustion chamber wall. This allows the orifice geometry to be optimized locally for stress distribution while maintaining cooling functionality.
Solution Approach 2:
The invention changes the geometric parameters of the orifice cross-section based on the mechanical stress parameters. By calculating the principal stress directions at each orifice location and adjusting the tool cross-section orientation and shape accordingly, the patent transforms the fixed circular cross-section parameter into a variable parameter that adapts to local stress conditions, thereby reducing stress concentration.
2Ease of manufacture
If multiple orifices are oriented in the same direction to simplify manufacturing, then manufacturing ease is improved, but aerodynamic disturbances occur due to non-homogeneous airflow
Solution Approach 1:
The patent applies local quality by orienting each orifice according to its local requirements. Rather than imposing a uniform orientation on all orifices, the invention allows each orifice's cross-section and orientation to be adapted to its specific location on the combustion chamber wall, optimizing both stress distribution and airflow characteristics for each local region.
Solution Approach 2:
The invention introduces dynamics by making the orifice orientation and cross-section adjustable rather than fixed. The tool cross-section can be varied during the perforation process to achieve different orientations and shapes for different orifices, allowing the system to adapt to local conditions while maintaining manufacturing feasibility through a controlled variation approach.
3Strength
If orifices are oriented with major axis perpendicular to combustion chamber axis to reduce stress concentration, then crack formation is delayed, but airflow homogeneity deteriorates
Solution Approach 1:
The patent resolves this contradiction by applying local quality - each orifice's cross-section orientation is specifically adapted to its local stress conditions rather than using a universal orientation. The tool cross-section is calculated and adjusted for each orifice location based on the principal stress directions at that specific point, allowing optimal stress distribution locally while maintaining overall airflow homogeneity through coordinated orientation selection.
Solution Approach 2:
The invention changes the orientation parameter of each orifice cross-section based on calculated stress parameters. By dynamically adjusting the tool cross-section orientation and shape for each orifice location, the patent transforms the fixed orientation parameter into a variable one that optimizes stress distribution locally while considering the overall airflow pattern to avoid excessive aerodynamic disturbances.
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 method effectively minimizes stress concentrations, prevents cracks and fissures, and maintains undisturbed airflow within the combustion chamber, enhancing its lifespan and operational efficiency.
Implementation Method 1
These openings are usually made by laser drilling
Implementation Method 2
the opening is created by bypassing
Implementation Method 3
The air passing through these points lowers the temperature of the walls and subsequently the entire combustion chamber
Implementation Method 4
due to the high temperatures of the combustion chamber, its internal and external walls generally require cooling
Implementation Method 5
the internal and external walls of the combustion chamber expand thermally in a heterogeneous manner
Data Source
Figure 1~4
Figure 5A~5E
Figure 6~6C
AI summary
The invention relates to a method for perforating a wall (12, 13). The method (100) comprises a first step (101) of calculating the mechanical stresses applied to said wall (12, 13) for a use of said wall (12, 13) and a second step (102) of piercing at least one orifice (21) in a first determined zone of said wall (12, 13), said perforation (102) being performed using a tool that has a cross section dependent on the calculated mechanical stresses in said first determined zone. The method of perforation finds a particularly beneficial application in the aeronautical domain.