Louvered Bleed Conduit Inlet for Gas Turbine Noise Reduction
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Solution Overview
Problem
Gas turbine engine bypass ducts generate unwanted tonal noise due to resonance and vibration modes, particularly when the bleed conduit control valve is in a shut or partially opened position, without significant aerodynamic losses.
Innovation Solution
Incorporating a scoop into the bypass duct wall with a bleed conduit inlet and a louver extending between lateral sides, where the louver's leading edge is within the fluid flow path and the trailing edge is within the bleed conduit, to direct fluid flow and reduce pressure loss while minimizing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a control valve is used to control fluid flow through the bleed conduit, then fluid flow control is improved, but tonal noise is generated due to resonance and vibration modes
Solution Approach 1:
A louver assembly is introduced as an intermediary component between the bypass duct and bleed conduit. The louver assembly includes multiple louvers that can be rotated to different angles to control fluid flow while disrupting resonance patterns and reducing tonal noise generation at the bleed conduit inlet
Solution Approach 2:
The louver assembly is designed with rotatable louvers that can dynamically adjust their angle of attack. This dynamic adjustment allows optimization of fluid flow control while simultaneously managing noise levels by changing the flow distribution pattern across the bleed conduit inlet
2Object-generated harmful factors
If the control valve is in a shut or partially opened position, then noise control is improved, but aerodynamic losses increase
Solution Approach 1:
The fluid flow control function is segmented between the control valve and the louver assembly. The louver assembly handles flow distribution and noise reduction, while the control valve maintains precise flow control. This segmentation allows the system to operate in partially closed positions without excessive noise or energy loss
3Productivity
If a bleed conduit is used to extract fluid from the bypass duct, then fluid extraction is improved, but unwanted tonal noise is generated
Solution Approach 1:
The louver assembly serves as an intermediary between the bypass duct and bleed conduit, extracting fluid while disrupting the flow patterns that generate tonal noise. The multiple louvers create a distributed flow extraction pattern that reduces resonance and vibration modes
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 tonal noise emissions while maintaining low aerodynamic losses, improving the bleed system's performance by directing fluid flow efficiently and reducing resonance-induced noise.
Implementation Method 1
the at least one louver further extends between a leading edge and a trailing edge opposite the leading edge. The leading edge is located within the bypass flow path and the trailing edge is located within the bleed conduit
Data Source
AI summary
A gas turbine engine includes a bypass duct extending about a longitudinal centerline of the gas turbine engine. The bypass duct includes at least one bypass duct wall defining at least a portion of a bypass flow path through the bypass duct. The at least one bypass duct wall includes a scoop extending into the bypass flow path. The gas turbine engine further includes a bleed conduit including an inlet connected to the bypass duct within the scoop of the at least one bypass duct wall and at least one louver mounted to the bleed conduit within the inlet. The at least one louver extends between a leading edge and a trailing edge opposite the leading edge. The leading edge is located within the bypass flow path and the trailing edge is located within the bleed conduit.