Acoustic Micropump Phase Control for Directional Fluid Flow
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Solution Overview
Problem
Existing micropump devices face challenges such as low pumping flow rate, high input power consumption, energy inefficiency, and limited flexibility in fluid flow direction due to mechanical complexities and non-directional acoustic wave propagation.
Innovation Solution
An acoustic micropump device utilizing piezoelectric transducers organized into sets of at least three groups, actuated by phase-shifted electrical control signals to create a net fluid flow, enabling high pumping velocity and flexible flow direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a silicon-based diaphragm piezoelectric micropump device is used, then high pumping flow rate is achieved, but the device requires complicated design and complex fabrication of inlet and outlet valves
Solution Approach 1:
The patent removes the complex inlet and outlet valve mechanisms from the micropump design. Instead of using traditional mechanical valves, the invention employs acoustic radiation pressure and streaming effects to achieve directional fluid flow, thereby simplifying the overall device structure while maintaining high pumping flow rate capability
Solution Approach 2:
The patent replaces mechanical valve systems with an acoustic field-based control mechanism. By using piezoelectric transducers to generate acoustic waves and resulting streaming flows, the system achieves fluid direction control without mechanical moving parts, reducing design and fabrication complexity
2Productivity
If a silicon-based diaphragm piezoelectric micropump device is used, then high pumping flow rate is achieved, but very high input power is required
Solution Approach 1:
The patent operates piezoelectric transducers at resonant frequencies to maximize acoustic wave generation efficiency. By tuning the operating parameters (frequency, amplitude) to match the resonant characteristics of the acoustic cavity and fluid system, the device achieves high pumping flow rates with reduced input power requirements compared to non-resonant operation
3Reliability
If surface acoustic wave (SAW) micropump device is used, then no mechanical moving parts are required, but the acoustic wave propagates non-directionally resulting in energy inefficiency
Solution Approach 1:
The patent introduces asymmetry in the acoustic field distribution by using specific transducer geometries and positioning strategies. This creates asymmetric acoustic radiation pressure and streaming patterns that drive fluid flow in a preferred direction, converting the previously non-directional SAW propagation into a directionally controlled flow mechanism with improved energy efficiency
Solution Approach 2:
The patent transitions from two-dimensional SAW propagation on a surface to three-dimensional acoustic cavity modes that confine and direct acoustic energy volumetrically. This dimensional transition enables directional control of acoustic streaming while maintaining the advantage of having no mechanical moving parts
4Reliability
If surface acoustic wave (SAW) micropump device is used, then no mechanical moving parts are required, but low pumping flow rate is achieved
Solution Approach 1:
The patent employs periodic excitation of piezoelectric transducers at resonant frequencies to generate sustained acoustic waves. This periodic action creates steady acoustic streaming flows that maintain consistent pumping performance, achieving higher flow rates compared to non-resonant or aperiodic operation while preserving the mechanical reliability advantage
Solution Approach 2:
The patent uses composite structures combining piezoelectric materials with acoustic cavity designs that enhance acoustic wave generation and streaming effects. This composite approach maximizes the conversion efficiency from electrical to acoustic energy, thereby achieving higher pumping flow rates without introducing mechanical moving parts
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 device achieves a high pumping flow rate of several hundreds of µL/min with low input power and flexible flow direction control, overcoming the limitations of existing technologies.
Implementation Method 1
the micropump device employs piezoelectric transducers, which are controlled in at least three groups
Implementation Method 2
Acoustic streaming refers to a fluid flow, which is induced by the force arising from the presence of a gradient in the time-averaged acoustic momentum flux inside the fluid domain
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
The present disclosure relates to a micropump device for creating a net fluid flow along a flow direction. The device comprises a fluid channel and a plurality of piezoelectric transducers arranged adjacent to the fluid channel. The piezoelectric transducers are organized into a set of at least three groups, the groups being consecutively arranged along the flow direction, and each comprising at least one piezoelectric transducer. A controller of the device is configured to actuate the piezoelectric transducers using at least three periodic electrical control signals, each electrical control signal being associated with one group of the set. The controller is configured to consecutively delay the at least three electrical control signals to another, in accordance with the consecutively arranged groups of the set, to create the net flow of fluid along the flow direction.