Piezoelectric Oscillating Surface Actuator for High-Frequency Flow Control
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Solution Overview
Problem
Current dynamic roughness technologies for flow control, such as compressed air driven dimples and electroactive polymers, face limitations including low frequency response, complex mechanical designs, high energy consumption, and vulnerability to weather conditions, which restrict their effectiveness in exciting flow fields and practical applications like aircraft control.
Innovation Solution
A piezoelectric driven oscillating surface actuator with a compliant layer and a chamber filled with fluid, where the piezoelectric surface displaces fluid to create controlled dimples, allowing for adjustable frequency and amplitude of roughness elements without complex plumbing or high voltage requirements, and is resistant to environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If compressed air driven dimples are used for dynamic roughness, then high levels of roughness displacement can be achieved, but the frequency response is extremely low and cannot excite the flow's natural frequencies
Solution Approach 1:
The patent replaces the compressed air mechanical system with a piezoelectric actuator system. The piezoelectric material converts electrical signals directly into mechanical displacement of the compliant layer, eliminating the need for compressed air plumbing while achieving the required frequency response for flow excitation.
Solution Approach 2:
The patent uses a fluid-filled chamber with a piezoelectric actuator to create pressure variations that deform the compliant layer. This hydraulic approach allows the piezoelectric element to generate the necessary forces for large amplitude roughness elements at high frequencies without direct mechanical linkage.
2Shape
If mechanically driven pistons are used for dynamic roughness, then high deflections can be achieved, but the mechanical design becomes very complex and heavy
Solution Approach 1:
The patent replaces complex mechanical piston systems with a piezoelectric actuator that directly deforms the compliant layer. This substitution eliminates elaborate mechanical linkages, reducing both design complexity and weight while maintaining the ability to achieve high roughness deflections.
Solution Approach 2:
The patent uses a compliant layer as a flexible membrane that directly forms the roughness elements when deformed by the piezoelectric actuator. This eliminates the need for rigid mechanical structures and complex linkages, simplifying the overall design while enabling large amplitude motions.
3Speed
If electroactive polymers (EAPs) are used for dynamic roughness, then the actuator can reach required frequencies without complex plumbing, but the deflection capability is limited to about 0.1 mm
Solution Approach 1:
The patent combines a piezoelectric material with a compliant layer to create a composite actuator system. The piezoelectric material provides the actuation force at high frequencies, while the compliant layer amplifies this motion into large amplitude roughness elements, overcoming the deflection limitations of EAPs.
Solution Approach 2:
The compliant layer acts as an intermediary between the piezoelectric actuator and the fluid flow. It amplifies the small displacements of the piezoelectric element into large amplitude roughness elements, enabling both high frequency operation and large deflection capability.
4Speed
If EAPs are used for dynamic roughness, then high voltages on the order of 1,000 V are required, increasing energy consumption
Solution Approach 1:
The patent replaces EAPs with piezoelectric actuators that operate at lower voltages. Piezoelectric materials convert electrical energy to mechanical energy more efficiently at lower voltage levels, reducing the energy consumption required for actuation while maintaining the ability to operate at flow-exciting frequencies.
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 piezoelectric driven oscillating surface actuator enables efficient control of fluid flow by generating significant dimple displacements at high frequencies, reducing energy consumption, and being resilient to environmental factors, thus overcoming the limitations of existing technologies.
Implementation Method 1
a piezoelectric surface mechanically coupled to the chamber, wherein the piezoelectric surface is configured to displace the fluid in the chamber
Data Source
AI summary
Disclosed herein is an active roughness actuator and a method of forming an active roughness actuator. The active roughness actuator includes a surface having at least one aperture; a compliant layer disposed on the surface such that the compliant layer covers the at least one aperture; a chamber having a fluid therein and a piezoelectric surface mechanically coupled to the chamber. The chamber is in fluid communication with the compliant layer via the at least one aperture. The piezoelectric surface is configured to displace the fluid in the chamber to control production of at least one dimple in the compliant layer proximate to the at least one aperture.