Flexible-Membrane Outlet Guide Vane for Turbine Noise Reduction
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Solution Overview
Problem
Conventional outlet guide vanes in gas turbine engines generate noise due to unsteady pressures at the leading edge, which can be exacerbated by holes or porous areas designed to reduce noise, leading to increased aerodynamic losses and reduced strength.
Innovation Solution
Incorporating a flexible membrane with a lower modulus of elasticity than the aerofoil body along the pressure and/or suction surfaces of the outlet guide vane, which dampens unsteady pressures at the leading edge without significantly affecting aerodynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If holes or porous areas are incorporated into the outlet guide vane to reduce noise, then noise generation is reduced, but aerodynamic losses increase and structural strength decreases
Solution Approach 1:
A flexible membrane is applied to the outer surface of the outlet guide vane, specifically on the pressure surface and/or suction surface. This membrane has a lower modulus of elasticity than the aerofoil body (at least 2 times lower), allowing it to flex and dampen unsteady pressures at the leading edge, thereby reducing noise without creating holes or porous areas that would compromise structural strength.
Solution Approach 2:
The outlet guide vane combines a rigid aerofoil body made of a material with high modulus of elasticity with a flexible membrane made of a material with low modulus of elasticity. This composite structure allows the rigid body to maintain structural strength while the flexible membrane dampens unsteady pressures to reduce noise generation.
2Object-generated harmful factors
If holes or porous areas are incorporated into the outlet guide vane to reduce noise, then noise generation is reduced, but aerodynamic performance deteriorates
Solution Approach 1:
The flexible membrane maintains the continuity of the aerofoil surface, preventing the formation of holes or porous areas that would cause aerodynamic losses. The membrane flexes to dampen unsteady pressures at the leading edge, reducing noise while preserving smooth airflow and minimizing aerodynamic losses.
Solution Approach 2:
The combination of rigid aerofoil body and flexible membrane creates a composite structure that maintains aerodynamic surface integrity. The flexible membrane dampens unsteady pressures without disrupting airflow, thereby reducing noise while preserving aerodynamic performance and minimizing energy losses.
3Object-generated harmful factors
If a flexible membrane is added to reduce noise, then noise generation is reduced, but device complexity increases
Solution Approach 1:
The flexible membrane is applied as a thin film or coating on the outer surface of the outlet guide vane, rather than requiring complex internal structures or multiple components. This simple application method reduces noise through the membrane's flexibility and ability to dampen unsteady pressures, while adding minimal structural complexity.
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 flexible membrane reduces noise generation during operation while maintaining or improving aerodynamic performance, with noise reduction benefits achieved through strategic placement and material selection.
Implementation Method 1
the flexible membrane may dampen an unsteady pressure generated at the leading edge of the aerofoil body, thereby reducing the noise generated during operation of the gas turbine engine
Implementation Method 2
The aerofoil body has a first modulus of elasticity and the flexible membrane has a second modulus of elasticity. The first modulus of elasticity of the aerofoil body is greater than the second modulus of elasticity of the flexible membrane by a factor of at least 2.
Data Source
AI summary
An outlet guide vane includes an aerofoil body including a root, a tip, a leading edge extending between the root and the tip, a trailing edge opposite to the leading edge, a pressure surface extending between the leading edge and trailing edge, and a suction surface extending between the leading edge and trailing edge opposite to the pressure surface. The outlet guide vane further includes a flexible membrane disposed along the pressure surface and/or the suction surface of the aerofoil body, such that the flexible membrane at least partially forms an outer surface of the outlet guide vane. The aerofoil body has a first modulus of elasticity and the flexible membrane has a second modulus of elasticity, wherein the first modulus of elasticity of the aerofoil body is greater than the second modulus of elasticity of the flexible membrane by a factor of at least 2.