Combustion Chamber Wall Multiperforation for Cooling and Manufacturing
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Solution Overview
Problem
Turbomachine combustion chamber walls experience inadequate cooling downstream of primary and dilution holes, leading to potential crack formation and increased manufacturing costs due to localized, expensive treatments.
Innovation Solution
An annular combustion chamber wall with additional holes having distinct intrinsic characteristics, such as varying number, inclination, and diameter, distributed in circumferential rows, provides effective cooling for these zones, simplifying drilling operations and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If localized treatment with transition holes is applied downstream of primary and dilution holes, then cooling effectiveness is improved, but manufacturing cost and time increase
Solution Approach 1:
The patent applies local quality by creating a localized zone of transition holes with different inclination angles specifically in the region downstream of primary and dilution holes, while other regions maintain the standard multiperforation angle. This targeted approach improves cooling effectiveness in the critical zone without requiring modification of the entire wall surface, thereby limiting the increase in manufacturing complexity to only the affected local area.
Solution Approach 2:
The cooling system is segmented into two distinct zones: a first zone with multiperforation holes at a standard inclination angle, and a second zone downstream of primary and dilution holes with transition holes at a different inclination angle. This segmentation allows each zone to be optimized independently for its specific thermal conditions, improving overall cooling effectiveness while enabling selective manufacturing approaches.
2Reliability
If additional cooling holes are added downstream of primary and dilution holes, then crack formation risk is reduced, but device complexity increases
Solution Approach 1:
Additional transition holes are introduced only in the specific region downstream of primary and dilution holes where thermal stresses are highest and crack formation risk is greatest. This localized addition of holes provides enhanced cooling and stress distribution exactly where needed, improving reliability without requiring a uniform increase in hole density across the entire combustion chamber wall.
Solution Approach 2:
The transition holes are positioned and designed in advance to preemptively address the high-risk zone for crack formation. By anticipating the thermal stress concentration downstream of primary and dilution holes, the design proactively introduces additional cooling pathways before cracks can develop, preventing the harmful effect rather than reacting to it.
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 solution ensures effective cooling of critical areas, preventing crack formation while reducing manufacturing time and costs by using holes with specific characteristics that are distributed in a manner facilitating efficient drilling.
Implementation Method 1
These multi-perforation orifices allow the air circulating outside the chamber to penetrate inside the latter by forming films of cooling air along the walls
Data Source
Figure 1
Figure 2~3
AI summary
Annular wall (6, 8) of combustion chamber (4) of turbomachine, having a cold side and a hot side, said wall being provided with a plurality of primary holes (18) and dilution holes (20) distributed in circumferential rows, a plurality of cooling orifices (22) distributed in a plurality of circumferential rows spaced axially apart from each other, the number of cooling orifices (22) being identical in each row, and a plurality of bores (24) disposed directly downstream of the primary holes (18) and dilution holes (20) and distributed in circumferential rows, the bores (24) of the same row having a substantially identical diameter, being spaced at a constant pitch (p2) and having intrinsic characteristics different from those of the cooling orifices (22) of the adjacent rows.