Distributed Fluidic Bleed Control for Aeroelastic Vibration Suppression
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Solution Overview
Problem
Conventional control surfaces for moving bodies in fluids face limitations such as significant weight, complexity, and mechanical damage, failing to provide sufficient control authority and leading to structural destabilization due to flutter vibrations.
Innovation Solution
A distributed active fluid bleed system that regulates bleed flow through actuated inlets and outlets, modifying aerodynamic forces and moments without introducing hard control surfaces, thereby enhancing control authority and mitigating flow-induced vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional control surfaces are used to control fluid flow around a moving body, then active control and regulation of fluid flow is achieved, but significant added weight and complexity are introduced
Solution Approach 1:
The patent employs porous structures integrated into the moving body surface that allow selective fluid passage. These porous materials enable active control of fluid flow by regulating porosity through actuation mechanisms, achieving control authority without traditional heavy control surfaces. The porous structure allows fluid to be bled from high to low pressure regions, modifying flow characteristics while maintaining structural integrity.
Solution Approach 2:
The system utilizes pneumatic actuation mechanisms to control the porosity of the structure. By introducing pressurized gas through channels to specific regions, the system can dynamically open or close porous pathways, thereby regulating fluid flow. This pneumatic control approach replaces complex mechanical control surfaces with a more compact and lighter system.
2Ease of operation
If conventional control surfaces are used for active control, then regulation of fluid flow is achieved, but mechanical damage and design limits reduce control authority
Solution Approach 1:
The porous structure provides inherent damage tolerance as it can withstand mechanical stresses better than traditional solid control surfaces. The distributed porous pathways throughout the structure allow fluid control without creating stress concentration points, reducing the risk of mechanical failure and enhancing reliability during operation.
Solution Approach 2:
The control system is divided into multiple distributed porous regions rather than a single large control surface. This segmentation allows localized control of fluid flow at different positions on the structure, and if one region is damaged, others can continue to function, maintaining overall system reliability and control authority.
3Ease of manufacture
If passive porosity is used for flow control, then aerodynamic flow control is achieved, but inability to alter control and continuous regulation over time is limited
Solution Approach 1:
The system transitions from static passive porosity to dynamic active porosity control. Actuation mechanisms are integrated with the porous structure to dynamically adjust the opening and closing of porous pathways in real-time. This allows the structure to adapt its porosity characteristics during operation, enabling continuous regulation of fluid flow in response to changing flight conditions or operational requirements.
Solution Approach 2:
The control system incorporates feedback mechanisms that monitor fluid flow conditions and structural response, then adjust porosity accordingly. Sensors detect parameters such as pressure distribution or flow rate, and this information feeds back to the actuation system to modulate porosity, achieving closed-loop control that provides time-dependent regulation capability.
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 system effectively modifies lift, pitching, and yawing moments, stabilizes structures, and suppresses aeroelastic vibrations, offering an alternative to traditional control surfaces with reduced weight and complexity.
Implementation Method 1
The one or more bleed inlets may receive the crossflow through the one or more bleed passages at a high pressure region of the crossflow. The one or more bleed outlets may release the received crossflow out into a low pressure region of the crossflow, thereby forming the bleed flow.
Data Source
AI summary
A system and method for regulating and actuating bleed over a structure exposed in a fluid motion are disclosed. The bleed inlet and outlet are formed on the surface of the structure establishing fluidic communication across surfaces. The disclosed system and method contemplates active control and regulation of the bleed to modify crossflow properties such as, aerodynamic forces, hydrodynamic forces, vorticity, and moments.