Engine Inlet Barrel Perforation Layout for Acoustic Open-Area Control
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Solution Overview
Problem
Conventional methods for forming acoustic perforations in gas turbine engine inlet barrels often result in blocked or missing perforations, leading to reduced noise reduction efficiency, increased production time, and costs, and are not adaptable to different structural configurations.
Innovation Solution
A system and method utilizing robotic drilling units to form elongated, non-circular perforations in a composite sandwich structure of the engine inlet barrel, allowing for synchronized drilling and precise control of percent-open-area to optimize acoustic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form perforations in the inner wall, then the inner wall can be formed as a separate component with perforations, but some perforations become blocked after assembly, reducing the percent-open-area and noise reduction effectiveness
Solution Approach 1:
The patent applies preliminary action by forming the perforations in the inner wall after the barrel section is fully assembled, rather than forming them in the separate inner wall component before assembly. This ensures that the perforation-forming operations occur at the precise final location and orientation, eliminating the risk of blockage during subsequent assembly steps while maintaining manufacturing feasibility through integrated positioning
Solution Approach 2:
The patent implements the nested doll principle by positioning the perforation-forming tooling within the already-assembled barrel section structure. The tooling is nested inside the barrel to access and form perforations in the inner wall from the interior side, allowing the operation to occur after assembly without requiring disassembly or complex external fixtures
2Productivity
If conventional methods are used to form perforations, then perforations can be created in the inner wall, but the process is time-consuming and increases production cost
Solution Approach 1:
The patent applies preliminary action by performing the perforation-forming operation after the barrel section is fully assembled but before final delivery. This timing allows all structural components to be in place, providing stable reference surfaces and precise positioning for the perforation tooling, thereby reducing rework and ensuring quality without extending overall production time
Solution Approach 2:
The patent implements self-service by designing the perforation-forming process to utilize the barrel section's own assembled structure as the positioning and support system. The inner wall and surrounding components serve as self-contained fixtures that guide the tooling and maintain precision, eliminating the need for additional external fixturing or assembly steps
3Ease of manufacture
If round holes are formed in the inner barrel, then the process is simple and effective, but the acoustic properties are insufficient to efficiently reduce sound
Solution Approach 1:
The patent applies local quality by varying the perforation geometry according to specific acoustic requirements at different locations in the inner wall. Rather than using uniform round holes throughout, the process forms perforations with shapes and dimensions optimized for local acoustic conditions, allowing simple manufacturing processes to produce acoustically effective results through location-specific customization
Solution Approach 2:
The patent implements parameter changes by modifying the geometric parameters of the perforations (shape, size, orientation, distribution) to optimize acoustic performance. The process can form elongated slots, varied hole diameters, and different patterns based on acoustic requirements, transforming the simple round hole approach into a parameter-adjustable system that maintains manufacturing simplicity while achieving superior noise reduction
4Reliability
If a unique pattern of circular holes is determined for each acoustic inlet barrel, then the acoustic properties can be optimized for that specific structure, but the process is time-consuming and the barrels cannot be substituted for different structures
Solution Approach 1:
The patent applies dynamics by making the perforation pattern adaptable and reconfigurable rather than fixed. The perforation-forming process can be programmed with different patterns and parameters, allowing the same barrel design to be optimized for different acoustic requirements or applications. This dynamic capability enables pattern customization without physical redesign, maintaining reliability while achieving versatility
Solution Approach 2:
The patent implements universality by creating a single barrel design that can serve multiple acoustic applications through programmable perforation patterns. The same basic barrel structure can be configured with different perforation geometries, densities, and arrangements to meet various acoustic requirements, allowing interchangeability and adaptability across different engine types or noise reduction targets while maintaining optimized performance
Data Source
AI summary
Certain embodiments of the present disclosure provide an acoustic inlet barrel of an engine. The acoustic inlet barrel may include an inner barrel configured to provide a boundary for directing airflow through the engine. The inner barrel may include an inner face sheet separated from an outer face sheet by an acoustic core. The inner barrel may include a plurality of elongated, non-circular perforations formed through the inner face sheet.