Trailing Edge Sheath Apertures for Gas Turbine Noise Reduction
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Solution Overview
Problem
Gas turbine engines experience noise emissions due to airflow interactions with stator vanes, leading to broadband and tonal noise, which existing solutions fail to adequately address without increasing engine weight.
Innovation Solution
A noise-reducing airfoil design featuring a trailing edge sheath with apertures that supply pressurized air to reduce wakes and velocity deficits, thereby minimizing noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If stator vanes are added to reduce air swirling motion, then momentum loss is reduced, but noise emissions increase
Solution Approach 1:
The patent uses the harmful high-velocity jet stream, which causes noise, and redirects it through ejector holes to serve a beneficial purpose: reducing the velocity deficit and enhancing the boundary layer on the airfoil surface, thereby reducing drag and noise simultaneously
Solution Approach 2:
The patent employs pneumatic principles by using compressed air from the jet stream itself, channeled through ejector holes, to create a controlled flow that modifies the boundary layer characteristics and reduces wake formation
2Object-generated harmful factors
If acoustic liners and exhaust mixers are used to reduce noise, then noise emissions are reduced, but engine weight increases
Solution Approach 1:
The system uses the engine's own jet stream as the source of compressed air for the ejector holes, making the noise reduction system self-sufficient without requiring external compressed air supplies or additional heavy infrastructure
Solution Approach 2:
The patent changes the flow parameters by introducing a controlled jet stream through ejector holes, which modifies the velocity distribution and boundary layer characteristics to reduce noise without adding heavy acoustic treatment materials
3Loss of energy
If jet stream is redirected through ejector holes to reduce velocity deficit, then drag is reduced, but system complexity increases
Solution Approach 1:
The airfoil surface is segmented with multiple ejector holes distributed across the surface, allowing the jet stream to be introduced at multiple locations to effectively reduce velocity deficit and drag without requiring a single complex system
Solution Approach 2:
The ejector holes serve multiple functions: they redirect the jet stream, reduce velocity deficit, enhance the boundary layer, and reduce drag, making a single simple feature perform multiple beneficial roles
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 airfoil design effectively reduces tonal noise by mitigating wakes and velocity deficits, improving noise reduction while maintaining performance and potentially reducing overall engine weight.
Implementation Method 1
The trailing edge sheath defines a fluid passageway extending along at least a portion of the span
Implementation Method 2
The at least one aperture may be configured to supply pressurized air from the fluid passageway to the outer surface to reduce wakes, velocity deficits, or both
Data Source
AI summary
A noise reducing airfoil defining a span extending between a root and a tip and a chord at each point along the span extending between a leading edge and a trailing edge. The airfoil includes a pressure side, a suction side, and a trailing edge sheath including an outer surface coupled to the trailing edge of the airfoil. The trailing edge sheath extends at least partially along the chord on the pressure and suction sides at each point along the span within the trailing edge sheath. The trailing edge sheath defines a fluid passageway extending along at least a portion of the span. Further, the trailing edge sheath defines at least one aperture on at least one of the pressure side, the suction side, or trailing edge fluidly coupling the fluid passageway to the outer surface.