Gas Turbine Cowl Assembly Indentations for Vortex Noise Reduction
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Solution Overview
Problem
Gas turbine engines experience significant noise and vibration due to correlated vortices forming at the trailing edge of moveable cowl assemblies, which impinge on the aft cowl during operation, leading to adverse effects.
Innovation Solution
The implementation of complementary indentations on the forward and aft cowl assemblies, which decorrelate the shedding of vortices by breaking up and timing the impingement, thereby reducing noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a moveable cowl assembly is used in a gas turbine engine, then the engine can achieve certain operational benefits, but correlated vortices form at the trailing edge and impinge on the aft cowl causing noise and vibration
Solution Approach 1:
The patent applies local quality by introducing complementary indentations at specific locations on the forward and aft cowls. These indentations are strategically positioned at the trailing edge of the forward cowl and corresponding areas on the aft cowl to locally modify the vortex shedding characteristics and reduce correlated vortex impingement, thereby reducing noise and vibration while preserving overall operational performance
Solution Approach 2:
The cowl assembly is segmented into multiple components with specific indentations introduced on the forward cowl, aft cowl, and intermediate cowls. This segmentation allows each component to be optimized independently for vortex control while maintaining the overall functionality of the moveable cowl assembly system
2Object-generated harmful factors
If complementary indentations are added to the cowl assemblies, then vortex shedding is decorrelated and noise/vibration are reduced, but the device complexity increases
Solution Approach 1:
The indentations are introduced as localized geometric modifications rather than complete redesign of the cowl structures. This approach reduces device complexity by making only necessary local changes to the forward cowl, aft cowl, and intermediate cowls, while preserving the overall simplicity and functionality of the cowl assembly system
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 effectively reduces noise and vibration by decorrelating vortices, enhancing the operational performance and reducing noise generation in gas turbine engines.
Implementation Method 1
correlated vortices forming at the trailing edge of moveable cowl assemblies, which impinge on the aft cowl during operation
Implementation Method 2
The implementation of complementary indentations on the forward and aft cowl assemblies, which decorrelate the shedding of vortices by breaking up and timing the impingement, thereby reducing noise and vibration
Data Source
AI summary
An aerodynamic device defining a thickness direction is provided. The aerodynamic device configured to produce lift or thrust or configured to be a part of an aerodynamic system that produces lift or thrust. The aerodynamic device includes a cowl assembly that defines at least in part an airflow stream. The cowl assembly includes a first cowl and a second cowl moveable relative to the first cowl. The first cowl includes a plurality of first cowl indentations at an end of the first cowl. The second cowl defines an outer surface along the thickness direction and an inner surface along the radial direction. The second cowl includes a plurality of second cowl indentations complementary in shape to the plurality of first cowl indentations. The plurality of second cowl indentations are positioned locally on the outer surface of the second cowl or locally on the inner surface of the second cowl.