The purpose of this paper is to present an overview of problems and some research gaps for better understanding of piezoelectric micropump studies. Micropumps have important and diverse application areas in health and engineering applications. In recent years, researchers have carried out simulations, analytical and experimental studies to develop these technologies with different methods for the same purpose. It has been determined that piezoelectric micropumps as MEMS devices have an effective deep interest. It is worth mentioning that piezoelectric material has been considered by researchers as an attractive actuator due to its high-performance, potential cost and design convenience. This paper comprehensively reviews the studies that bring innovations in the literature of piezoelectric micropumps. Analytical characterization and modeling procedures studied by various scientists in the field of the piezoelectric actuators are also presented in detail. The analytical section will mainly focus on the studies related to the static and dynamic behaviours of circular piezoelectric actuators. Moreover, the advantages and disadvantages of the various components used to fabricate micropumps have been investigated according to the available information in the literature. Consequently, this review enables researchers a useful reference on piezoelectric micropump parameters such as modeling, flow rate, shape control, geometry, and size optimization for key engineering applications.

Piezoelectric micropumps: state of the art review

With the combination of micropumps and flow sensors, highly accurate and secure closed-loop controlled micro dosing systems for liquids are possible. Implementing a single stroke based control mode with piezoelectrically driven micro diaphragm pumps can provide a solution for dosing of volumes down to nanoliters or variable average flow rates in the range of nL/min to μL/min. However, sensor technologies feature a yet undetermined accuracy for measuring highly pulsatile micropump flow. Two miniaturizable in-line sensor types providing electrical readout-differential pressure based flow sensors and thermal calorimetric flow sensors-are evaluated for their suitability of combining them with mircopumps. Single stroke based calibration of the sensors was carried out with a new method, comparing displacement volumes and sensor flow volumes. Limitations of accuracy and performance for single stroke based flow control are described. Results showed that besides particle robustness of sensors, controlling resistive and capacitive damping are key aspects for setting up reproducible and reliable liquid dosing systems. Depending on the required average flow or defined volume, dosing systems with an accuracy of better than 5% for the differential pressure based sensor and better than 6.5% for the thermal calorimeter were achieved.

The Combination of Micro Diaphragm Pumps and Flow Sensors for Single Stroke Based Liquid Flow Control

Current micropump technology features bubble tolerance and self-priming ability, achieved with high pressure ability at shallow pump chambers for low dead volume and high compression ratio. Though, the pump dynamics are strongly affected by a pump chamber height dependent viscous squeeze film damping. Therefore, we investigated all major flow influencing effects for micro diaphragm pumps, being liquid resistive damping, cavitation based gaseous capacitive damping and reactive valve volumes. Analytical models were developed that are able to describe and predict the transient actuator displacement, derive the frequency dependent displacement and estimate the valve loss effect in order to determine the flow rate performance of micropumps. In addition, a new oscillator model is able to simulate the inception of cavitation and the time course of both actuator and liquid. The individual effect models were combined into a single-cycle based, frequency dependent, flow rate model, validated for frequencies of up to 100 Hz. Compared to the maximum achievable flow rate, the liquid resistive damping reduces dynamic stroke volume and is responsible for a reduction of 23–57 % at 100 Hz. Valve induced flow losses reduce the effectively redirected volume towards the outlet. The effect is enhanced by the strong damping, but also feeds back on the actuator by reducing initial damping significantly. Reactive valve volumes amount for 6.2–12.4% flow rate reduction at 100 Hz. Full cavitation, generated at the supply mode and affecting the pump mode, can cause gas bubble generation and lead to a drop of flow rate down to 65% at 80 Hz. By placing an in-line degasser the flow stability was improved to ±2.2% over 10 h. After reducing the frequency to 20 Hz, cavitation only affected the supply mode and in combination with a degasser a flow stability of ±0.15% over 2 h was achieved. By reducing voltage levels, cavitation was avoided completely, featuring a stability of ±0.08%. The understanding of the flow rate limiting effects enables the application specific design to meet all performance and reliability requirements for micropump based liquid dosing systems.

Flow rate influencing effects of micropumps

In this paper, the design, modeling, and characterization of a display compatible pMUT platform are presented. A FEM model is built using COMSOL Multiphysics for evaluating the frequency response, mechanical performance, acoustic pressure, and driving efficiency of our pMUT device across all vibration modes of circular plates. In parallel with it, a first mode analytical model has been developed including electrical, mechanical, and acoustic domains to provide fast estimation for future design. A laser Doppler vibrometer is used to measure the frequency response, displacement, velocity as well as mode shapes of pMUTs with different designs in air. The measured resonance frequency of first mode range from 121.5kHz to 1.1MHz with radius from 500μm to 120μm and fits the prediction of FEM and analytical models. A standard reference microphone is used to measure the acoustic pressure of pMUT inside its frequency range (<125 kHz). The measured acoustic pressure on transverse axis of a 500μm radius pMUT also fits the values from analytical model on acoustic domain.

Design, modelling, and characterization of display compatible pMUT device

In this study, the static displacement behaviour of a three-layer axisymmetric circular piezoelectric unimorph actuator subjected to voltage and uniform pressure loads for different mechanical and geometric properties of layers was investigated. The closed-analytical model of piezoelectric actuator based on the classical laminated thin plate theory was performed. Kirchhoff’s thin plate theory for the mathematical model in closed form of the actuator was utilized. The superposition of transverse and lateral deflections expressions was used to obtain the displacement equation of the piezoelectric actuator. Then, the analytical model solutions were compared by finite element model solutions. It was observed that the results obtained from analytical model and finite element analysis were sufficiently compatible with each other. The effects of nondimensional physical and mechanical properties on the static deflection performance of the piezoelectric actuator were discussed using the analytical model. According to the results obtained, the physical and mechanical properties of the actuator had significant effects on the actuator displacement. Therefore, the results obtained in this study can be used to optimize the performance of the circular piezoelectric actuator.

Analytical analysis of a circular unimorph piezoelectric actuator in the range of low voltages and pressures

This paper presents an investigation of ideal geometry and material parameters of piezo-driven axisymmetric unimorph actuators for micropump applications. Based on Classic Laminated Plate Theory, closed form expressions for the transverse and radial displacement under diverse loads are derived for two types of unimorph actuators. The general approach allows an application of this theory to almost arbitrary actuator geometries. Using analytical and numerical methods, both actuators are optimized to achieve maximum stroke volume at predefined pressure conditions. In this process, strikingly simple expressions are found, constituting the theoretical maximum stroke volume of a circular bender type actuator. The optimization is complemented by a non-linear FEM study that confines the scope of the the analytical results. In summary, the optimization procedure presented in this paper facilitates the design of piezoelectrically driven unimorph diaphragm actuators by providing generic design rules regarding materials and geometrical dimensions.

Design of ideal circular bending actuators for high performance micropumps

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

David Horsch

Author Tools

Chat about Author

Papers

Design of ideal circular bending actuators for high performance micropumps