Annular Combustion Chamber Wall Cooling with Bent Multi-Perforation Holes
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Solution Overview
Problem
Annular turbine engine combustion chamber walls experience inadequate cooling around primary and dilution holes, leading to a risk of cracks due to low cooling levels, particularly downstream from these areas, as existing cooling methods rely solely on static air pressure.
Innovation Solution
The annular combustion chamber wall incorporates multi-perforation holes with bends greater than 90°, utilizing total air pressure on the cold side for enhanced cooling, while opening on the hot side like gyratory multi-perforation, thereby leveraging both axial and gyratory multi-perforation benefits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional axial multi-perforation orifices are used for cooling, then the cooling air film is formed along the shrouds, but the cooling effectiveness is reduced in zones downstream from primary and dilution holes due to static pressure feeding only
Solution Approach 1:
The patent changes the orientation parameter of cooling orifices from axial (parallel to flow direction) to inclined (at angle θ1 relative to normal N), and introduces bent multi-perforation holes with bends greater than 90°. These geometric parameter changes enable the cooling holes to be fed by total pressure rather than static pressure only, improving cooling effectiveness in high-temperature zones downstream from primary and dilution holes while reducing crack risk
Solution Approach 2:
The patent transitions from conventional axial multi-perforation (one-dimensional cooling along the flow direction) to inclined and bent multi-perforation holes that operate in multiple dimensions. The bent holes with angles greater than 90° create a three-dimensional cooling pattern that delivers cooling air more effectively to zones downstream from primary and dilution holes, overcoming the limitation of static pressure feeding
2Temperature
If gyratory multi-perforation orifices at 90° are used, then cooling is delivered effectively perpendicular to the flow direction, but the orifices are fed solely by static pressure of the air flowing around the combustion chamber
Solution Approach 1:
The patent modifies the orientation parameter of cooling orifices from axial (parallel to flow direction) to inclined (at angle θ1 relative to normal N), and introduces bent multi-perforation holes with bends greater than 90°. These geometric parameter changes enable the cooling holes to be fed by total pressure rather than static pressure only, improving cooling effectiveness in high-temperature zones downstream from primary and dilution holes while reducing crack risk
Solution Approach 2:
The patent introduces dynamic pressure utilization through inclined and bent multi-perforation holes. By orienting the holes at specific angles and introducing bends greater than 90°, the design captures the dynamic pressure component of the airflow, converting it into effective cooling flow. This dynamic approach contrasts with conventional static pressure feeding, enabling better utilization of the total pressure available in the airflow around the combustion chamber
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 design achieves effective cooling by utilizing dynamic air pressure, reducing the risk of cracks and improving heat exchange efficiency around high-temperature zones, combining the advantages of axial and gyratory multi-perforation methods.
Implementation Method 1
multi-perforation holes having respective bends of an angle α greater than 90°, said angle α being measured between an inlet axis Ae and an outlet axis As of said multi-perforation hole... utilizing total air pressure on the cold side for enhanced cooling
Implementation Method 2
a plurality of cooling orifices to enable the air flowing on said cold side to penetrate to said hot side in order to form a film of cooling air along said annular wall
Implementation Method 3
a plurality of air admission orifices distributed along at least one circumferential row to enable the air flowing on said cold side to penetrate to said hot side, said air admission orifices creating around them zones of steep temperature gradient
Data Source
AI summary
An annular turbine engine combustion chamber wall including air admission orifices to create zones of steep temperature gradient, and cooling orifices to enable the air flowing on the cold side to penetrate to the hot side in order to form a film of cooling air along the annular wall, the annular wall being further includes, in the zones of steep temperature gradient, multi-perforation holes having respective bends of an angle α greater than 90°, the angle α being measured between an inlet axis Ae and an outlet axis As of the multi-perforation hole, the outlet axis of the multi-perforation hole being inclined at an angle θ3 relative to the normal N to the annular wall through which the multi-perforation holes with bends are formed, in a “gyration” direction that is at most perpendicular to the axial flow direction D of the combustion gas.