Variable Outlet Guide Vane Actuation for Unducted Fan Noise
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Solution Overview
Problem
Unducted single fan engines generate significant acoustic noise due to the interaction of rotating fan blades and stationary outlet guide vanes, and existing solutions fail to effectively optimize aerodynamic performance and noise reduction across varying operating conditions.
Innovation Solution
The outlet guide vane is designed to be variable, allowing for adjustments in position, pitch, lean angle, and camber through the use of actuation devices such as shape memory alloys, mechanical, and electrical actuators, enabling independent control of each vane to optimize performance and reduce noise across different flight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If outlet guide vanes are made stationary to simplify structure, then device complexity is reduced, but aerodynamic performance and noise optimization across varying operating conditions deteriorates
Solution Approach 1:
The outlet guide vane system transitions from stationary to variable geometry, allowing the vanes to change pitch and orientation dynamically. This is achieved through actuation mechanisms that enable each vane to be independently controlled, optimizing aerodynamic performance across different operating conditions while managing the added complexity through systematic design
2Adaptability or versatility
If variable outlet guide vanes are implemented to optimize aerodynamic performance and noise reduction, then adaptability is improved, but device complexity increases
Solution Approach 1:
The outlet guide vane system is divided into multiple independently controllable segments or vanes. Each vane can be actuated separately, allowing for fine-tuned control of the flow field. This segmentation enables optimized aerodynamic performance while the modular approach helps manage system complexity through distributed control
Solution Approach 2:
The patent replaces complex mechanical pitch control mechanisms with alternative actuation methods. Shape memory alloys and other smart materials are used to achieve vane rotation and pitch changes through material deformation rather than traditional mechanical linkages, significantly reducing the complexity of the control system while maintaining variable geometry capability
3Productivity
If complex pitch control mechanisms are used to achieve variable outlet guide vanes, then aerodynamic performance is optimized, but weight and cost increase
Solution Approach 1:
Traditional mechanical pitch control systems with motors, linkages, and actuators are replaced with shape memory alloy-based actuation. These smart materials change shape in response to temperature or electrical stimuli, enabling vane rotation without heavy mechanical components. This substitution dramatically reduces the weight of the moving parts while maintaining the ability to optimize aerodynamic performance across different operating conditions
4Reliability
If traditional mechanical actuation devices are used for outlet guide vane control, then reliability is improved, but weight and device complexity increase
Solution Approach 1:
The patent replaces traditional mechanical actuation devices with shape memory alloy-based systems. These materials provide reliable actuation through their inherent phase transformation properties, eliminating the need for complex mechanical linkages, gears, and motors. The solid-state nature of shape memory alloy actuators improves reliability by reducing moving parts that could fail, while simultaneously reducing weight
Solution Approach 2:
Shape memory alloy actuators are self-actuating through their material properties. When subjected to appropriate thermal or electrical stimuli, they automatically change shape to rotate the vanes without requiring external mechanical transmission systems. This self-service capability reduces weight and complexity while maintaining reliable control, as the actuation function is embedded in the material itself rather than requiring separate mechanical components
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
This solution reduces noise levels, enhances engine efficiency, minimizes weight and cost, eliminates the need for complex pitch control mechanisms, and allows for improved packaging and maintenance, while maintaining optimal aerodynamic performance from takeoff to cruise.
Implementation Method 1
an actuation device, such as a mechanical activation, electrical activation, or through use of a shape memory alloy
Implementation Method 2
an actuation device, such as a mechanical activation, electrical activation, or through use of a shape memory alloy, or any combination
Data Source
AI summary
An unducted single fan engine includes a housing having one or more fan blades coupled to the housing and configured to rotate circumferentially. The engine has one or more outlet guide vanes coupled to the housing. Each of the one or more guide vanes has a leading edge portion having a variable leading edge. The engine has one or more actuation devices coupled to each of the one or more outlet guide vanes. The one or more actuation devices are configured to control the variable leading edge of the respective outlet guide vane. The variable leading edge is controllable to vary the pitch, camber, lean angle, or sweep of the respective outlet guide vane.