Plasma Actuators for Fan Boundary Layer Control
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Solution Overview
Problem
Fan and ducted-fan performance at low Reynolds numbers is limited by boundary layer separation, leading to reduced propulsion efficiency and increased noise, particularly in small-scale applications such as micro air vehicles and computer cooling systems, where conventional blade designs struggle to generate sufficient lift and efficiency.
Innovation Solution
The use of dielectric barrier discharge plasma actuators, driven in high-frequency steady or pulsed modes, to control air flow and prevent boundary layer separation, thereby enhancing aerodynamic performance and reducing power consumption and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional blade designs are used at low Reynolds numbers, then the structure is simple and easy to manufacture, but boundary layer separation occurs leading to reduced propulsion efficiency and increased noise
Solution Approach 1:
The patent replaces conventional mechanical flow control methods (such as moving parts or mechanical actuators) with a plasma-based system. Dielectric barrier discharge plasma actuators generate ionized gas that interacts with the boundary layer through electrohydrodynamic forces, eliminating the need for mechanical moving parts while effectively controlling flow separation and reducing noise.
Solution Approach 2:
The patent changes the physical state of the fluid by introducing plasma (ionized gas) into the boundary layer. This alters the local fluid properties including density, viscosity, and electrical conductivity, enabling active control of the boundary layer to prevent separation and improve propulsion efficiency without increasing mechanical complexity.
2Productivity
If plasma actuators are added to fan blades, then aerodynamic performance and propulsion efficiency are improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical flow control systems with plasma actuators that have no moving parts. The dielectric barrier discharge actuators consist of simple electrode-dielectric configurations that generate plasma when energized, providing flow control through electrohydrodynamic forces rather than mechanical means, thus improving propulsion efficiency without adding mechanical complexity.
Solution Approach 2:
The plasma actuator system serves multiple functions: it controls boundary layer separation, reduces noise, and can be applied to various fan blade designs and configurations. The same basic actuator design can be used across different applications and Reynolds number regimes, providing universal flow control capability that justifies the added complexity through multifunctional performance enhancement.
3Volume of moving object
If fan size is reduced for small-scale applications, then the system becomes more compact and suitable for micro air vehicles, but Reynolds number decreases causing severe boundary layer separation
Solution Approach 1:
The patent changes the physical parameters of the flow by introducing plasma into the boundary layer. This modifies local fluid properties and creates electrohydrodynamic forces that actively control the boundary layer, preventing separation even at the low Reynolds numbers characteristic of small-scale and micro air vehicle applications, thereby maintaining propulsion efficiency in compact designs.
Solution Approach 2:
The patent replaces conventional mechanical solutions for achieving lift and propulsion at small scales with plasma-based flow control. Instead of relying on larger blade surfaces or higher speeds to overcome boundary layer separation, the system uses dielectric barrier discharge actuators to generate plasma that actively manages the boundary layer, enabling effective propulsion in compact configurations.
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
Significant improvements in thrust generation and energy efficiency are achieved, with up to 50% reduction in power consumption and 75% decrease in noise levels, making the technology suitable for various applications including micro air vehicles and computer cooling systems.
Implementation Method 1
Dielectric barrier discharge plasma actuators are preferably used
Implementation Method 2
The use of dielectric barrier discharge plasma actuators, driven in high-frequency steady or pulsed modes, to control air flow
Data Source
AI summary
The current invention provides significant performance improvements or significant energy savings for fans used in these applications: personal, industrial and automotive cooling, ventilation, vacuuming and dust removal, inflating, computer component cooling, propulsors for unmanned and manned air vehicles, propulsors for airboats, air-cushion vehicles, airships and model aircraft. Additionally, the invention provides higher performance such as higher lift and higher lift efficiency to small air vehicles. These advantages are achieved by using plasma actuators to provide active flow control effectors into thin fan blades and wing.