Plasma Flow Control on Coanda Surfaces
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Solution Overview
Problem
Conventional control systems for airborne mobile platforms, such as aircraft, face challenges in achieving aerodynamic efficiency and stability without bulky infrastructure and moving parts, particularly in tailless configurations and high-speed vehicles.
Innovation Solution
The use of plasma flow actuators on a Coanda surface, controlled by a high voltage AC source, to ionize air and influence boundary layer flow, delaying or promoting separation, thereby enhancing control and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional control surfaces are used, then aerodynamic control is achieved, but aerodynamic efficiency and structural efficiency are reduced
Solution Approach 1:
The patent replaces conventional mechanical control surfaces with plasma actuators that use electromagnetic fields to control boundary layer flow. The plasma actuators generate body forces through ionization and acceleration of charged particles in the boundary layer, eliminating the need for heavy mechanical control surfaces while maintaining aerodynamic control capability.
Solution Approach 2:
The patent changes the physical state of air in the boundary layer from neutral to ionized plasma by applying high voltage AC signals to electrodes. This parameter change enables direct electromagnetic actuation of the boundary layer flow, providing control without mechanical moving parts and improving both aerodynamic and structural efficiency.
2Reliability
If pneumatic control devices are used, then aerodynamic control potential is achieved, but device complexity and weight increase due to high pressure air supply infrastructure
Solution Approach 1:
The patent replaces pneumatic control systems with plasma actuators that use electrical energy to generate body forces directly in the boundary layer. This substitution eliminates the need for bulky high-pressure air supply infrastructure, reducing device complexity and weight while maintaining aerodynamic control potential.
Solution Approach 2:
The patent employs periodic AC voltage excitation at specific frequencies (e.g., 1 kHz to 100 kHz) to generate oscillating body forces in the boundary layer. This periodic action creates effective flow control and aerodynamic control without requiring continuous high-pressure air supply, simplifying the overall system.
3Reliability
If acoustic control devices with moving parts are used, then boundary layer modification is achieved, but device complexity increases due to numerous moving parts
Solution Approach 1:
The patent replaces acoustic control devices with moving parts with plasma actuators that use electromagnetic fields to directly modify boundary layer flow. The plasma actuators generate body forces through ionization and acceleration of charged particles, eliminating the need for complex mechanical and acoustic subsystems with moving parts.
Solution Approach 2:
The plasma actuators generate their own body forces through electromagnetic interaction with the boundary layer plasma, without requiring external mechanical or acoustic systems. The system is self-sufficient, using electrical energy to create the necessary flow modification forces directly at the boundary layer.
4Loss of energy
If plasma actuators are used to delay boundary layer separation, then aerodynamic efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent employs periodic AC voltage excitation at optimized frequencies to generate oscillating body forces that efficiently delay boundary layer separation. The periodic action allows for effective flow control with reduced energy consumption compared to continuous actuation, as the oscillating forces can leverage the natural flow characteristics and timing.
Solution Approach 2:
The patent optimizes plasma actuator parameters including voltage amplitude, frequency, and electrode configuration to achieve maximum aerodynamic benefit with minimum energy consumption. By carefully controlling the plasma generation and body force generation parameters, the system achieves efficient boundary layer control without excessive energy input.
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 approach enables improved aerodynamic and structural efficiency, reduces drag, and provides hingeless yaw control, increasing agility and performance while simplifying designs and reducing weight and complexity.
Implementation Method 1
A voltage is applied to the plasma actuator and controlled to ionize air in a vicinity of the plasma actuator adjacent to the trailing edge
Implementation Method 2
plasma actuators for drag reduction on aircraft wings and other surfaces. The plasma caps a directed momentum into the air surrounding the surface
Implementation Method 3
This causes an induced flow that operates to influence at least one of attachment or separation of a boundary layer flow over the trailing edge surface
Data Source
Figure 1
Figure 1A~2
Figure 3~4
AI summary
A flow control system and method especially well adapted for use on a Coanda surface (18). In one embodiment a plurality of plasma actuators (16a-16d) are disposed over a Coanda surface of a wing of an aircraft. The actuators are selectively energized to either delay the onset of boundary layer flow separation from the Coanda surface, or to promote flow separation. One embodiment discloses using dual mode plasma actuators on a Coanda surface. The system and method is applicable to a wide variety of aerodynamic surfaces where control over the separation of a boundary layer flow over a trailing edge surface is desired.