Synthetic Jet Actuator Fluid Sloshing Amplification

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Solution Overview

Problem

Current synthetic jet actuators using piezo electric actuators have limited diaphragm deflection motion due to their manufacturing constraints, which restricts the performance of synthetic jet actuators in increasing air flow velocity and volume.

Innovation Solution

A synthetic jet actuator system that employs a case with a cavity and an intermediate interface excited in a sloshing mode to alternately expand or reduce the cavity volume, using a fluid chamber or a gelatin-like substance to enhance diaphragm motion, and incorporates a Piezo electric actuator to excite the fluid, allowing for increased volumetric change and air flow manipulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If more flexible Piezo electric actuators are used to increase diaphragm deflection, then the stroke length increases, but the deflection or strains remain relatively small due to manufacturing constraints

Engineering Contradiction:

Improvediaphragm deflectionVSAvoidactuator manufacturing constraints

Core Design Contradiction:

Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediate fluid interface as a mediator between the Piezo electric actuator and the cavity. The fluid interface amplifies the small actuator deflection into large diaphragm motion through sloshing mode vibration, overcoming the manufacturing limitations of flexible Piezo actuators while achieving large stroke lengths.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes mechanical vibration by exciting the fluid in sloshing mode at resonant frequencies. This vibration amplifies the small actuator deflection into large-scale fluid motion and diaphragm deflection, transforming the limitation of small actuator strains into large effective stroke length.

Inventive Principle:

Principle #18Mechanical vibration

2Speed

If diaphragm displacement is increased to increase stroke length, then exit velocity and momentum increase, but current Piezo actuators cannot achieve sufficient deflection

Engineering Contradiction:

Improveexit jet stream velocityVSAvoiddiaphragm deflected motion

Core Design Contradiction:

SpeedVSLength of moving object

Solution Approach 1:

The patent changes the physical parameters of the system by introducing a fluid interface with specific density and viscosity properties. This allows the system to achieve large diaphragm deflection and high exit velocity by exploiting the fluid's sloshing mode resonance, rather than relying solely on actuator deflection magnitude.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

By exciting the fluid at its natural sloshing frequency, the system achieves resonant amplification of motion. This mechanical vibration transforms small actuator deflections into large diaphragm motions and high exit jet velocities, resolving the contradiction between limited actuator deflection and desired high-speed performance.

Inventive Principle:

Principle #18Mechanical vibration

3Volume of moving object

If a fluid interface is introduced to amplify diaphragm motion, then cavity volume change increases, but device complexity increases

Engineering Contradiction:

Improvecavity volumetric changeVSAvoidactuator structure

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The fluid interface serves multiple functions simultaneously: it acts as a volume amplifier, a vibration mediator, and a motion transformer. This multi-functionality achieves large cavity volumetric change without proportionally increasing device complexity, as the same fluid element performs multiple roles in the system.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs hydraulic principles by using an incompressible fluid interface to transmit and amplify motion. The fluid's incompressibility ensures efficient volume transfer from the actuator chamber to the cavity, achieving large volumetric change with relatively simple structural additions.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 enhanced diaphragm motion and air flow manipulation result in increased exit velocity and fluid momentum, improving the aerodynamic efficiency of synthetic jet actuators.

Implementation Method 1

Methodology Applied

Scientific EffectPiezo electric effect: Piezoelectric Effect

Implementation Method 2

The intermediate interfaced is excited in a sloshing mode to expand or reduce the volume of the cavity thereby entraining air into or expelling air from the cavity

Methodology Applied

Scientific EffectSloshing mode vibration: Vibration

Data Source

PatentUS8931714B1Apparatus and method for an improved synthetic jet actuator

Publication Date: 2015.01.13 THE BOEING CO

AI summary

A synthetic jet actuator employs a case having a cavity with an orifice. An intermediate interface is contained within the case adjacent the cavity. The intermediate interfaced is excited in a sloshing mode to expand or reduce the volume of the cavity thereby entraining air into or expelling air from the cavity.