Plasma Actuator Boundary Layer Flow Control
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Solution Overview
Problem
Aerodynamically efficient airborne mobile platforms, such as aircraft, face challenges in directional control at low to moderate angles of attack without conventional control surfaces, and existing control systems add significant weight due to hinges and actuators.
Innovation Solution
A plasma actuator system with electrodes and a dielectric material is used to control boundary layer flow over a mobile platform's surface, allowing for selective prevention or induction of boundary layer separation by applying AC voltage, reducing the need for conventional control surfaces and actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional hinged panels and mechanical actuators are used for flow control, then directional control at low to moderate angles of attack is achieved, but weight increases significantly
Solution Approach 1:
The patent replaces conventional mechanical control surfaces (hinged panels and actuators) with a plasma actuator system that uses ionized gas to manipulate boundary layer flow. The plasma actuator employs electrodes that generate electric fields to ionize air molecules, creating a plasma region that exerts body forces on the boundary layer to control flow separation and enable directional control without mechanical moving parts.
Solution Approach 2:
The plasma actuator controls flow by changing the electrical parameters (voltage, frequency, power) of the applied electric field. By modulating these electrical parameters, the actuator can dynamically adjust the intensity and distribution of plasma body forces acting on the boundary layer, enabling precise control of flow separation characteristics and directional control at various angles of attack.
2Loss of energy
If conventional control surfaces are removed to improve aerodynamic efficiency, then aerodynamic performance improves, but stability and control characteristics deteriorate
Solution Approach 1:
The plasma actuator system provides aerodynamic control without mechanical control surfaces, maintaining the streamlined configuration for aerodynamic efficiency while delivering the necessary flow control authority for stability and directional control through non-mechanical plasma body forces.
Solution Approach 2:
The plasma actuator operates by applying periodic AC voltage to the electrodes, creating oscillating electric fields that generate time-varying plasma body forces. This periodic actuation effectively manipulates the boundary layer flow to control separation and provide directional control, demonstrating dynamic control capability without mechanical moving parts.
3Ease of operation
If hinged panels and linkage are used for control, then flow control capability is achieved, but device complexity increases
Solution Approach 1:
The plasma actuator eliminates complex mechanical linkages, hinges, and actuators by using electric fields to directly manipulate the boundary layer flow. The system consists of electrodes mounted on the airframe that generate plasma when voltage is applied, providing flow control through electromagnetic interactions rather than mechanical means, thereby significantly reducing device 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 plasma actuator system provides efficient directional control and reduces weight by eliminating the need for hinged panels and mechanical actuators, enhancing flight performance and payload capacity.
Implementation Method 1
applying an AC voltage across a pair of electrodes to cause ionization of air between the pair of electrodes
Implementation Method 2
A plasma actuator system with electrodes and a dielectric material is used to control boundary layer flow
Implementation Method 3
A dielectric material is disposed between the third electrode and the first and second electrodes
Data Source
AI summary
A plasma actuator system and method especially well adapted for use on airborne mobile platforms, such as aircraft, for directional and/or attitude control. The system includes at least one plasma actuator having first and second electrodes mounted on a surface of an aircraft. The first and second electrodes are arranged parallel to a boundary layer flow path over the surface. A third electrode is mounted between the first and second electrodes and laterally offset from the first and second electrodes. A high AC voltage signal is applied across the first and third electrodes, which induces a fluid flow between the energized electrodes that helps to delay separation of the boundary layer. Applying the AC voltage across the second and third electrodes causes an induced fluid flow that creates the opposite effect of influencing the boundary layer flow to separate from the surface. A plurality of the actuators can be selectively placed at various locations on the aircraft, and selectively energized to provide directional control and/or attitude control over the aircraft.