Papers by Keyword: Valveless Micropump

Abstract: This paper proposes a novel approach for micropump driven, namely laser shock wave, with the advantages of high energy efficiency, remote control and wireless energy supply. The pump used here has the characteristics of simple structure, easy fabrication and low cost comparing to the traditional micropump. Firstly, a valveless micropump was designed and then manufactured through lithography and bonding. Secondly, modal analysis of the fluid-structure coupling system, i.e. micropump, was calculated, and the first natural frequency was chosen as the frequency of the laser pulse. Finally, experiments were done to validate the feasibility of the driving mode. Results show the new driving mode works well and may provide an alternative approach for microsystem driven.

Abstract: Micropump is the key component in the micro total analytical system. The major technical impediment in improving the performance of this micro-device lies in the lack of understanding the physical phenomena and their interactions of electric, mechanical, and fluidic fields for performing their intended functions. Because of the complexity of the micropump, the full coupled numerical analysis is extremely needed. This paper presents for the results of such fully coupled simulations. CFDRC® was used for the transient analysis of an electrostatically actuated micropump. The results show that the dynamic characteristics of fluid in the micropump and the vibration of flexible diaphragm are highly interactive each other. The flow rectification of the nozzle/diffuser will work only after the pressure difference between the two ends of valve have reached at a critical value. In the pump chamber, the fluidic press distribution almost independent of the space variation. Due to the increasing demands for accuracy, the nonlinear features of viscous loss of the fluid can no longer be neglected or simplified, but have to be taken into account in detail.

Abstract: This paper presents a simple process technique for the fabrication of valveless micro-pumps. The process design utilizes standard MEMS process using double-sided anisotropic silicon wet etching process with an additional adhesive bonding technique. The diffuser and nozzle element of the pump with depth of 50 µm, as well as a 150 µm thick silicon membrane are designed and fabricated using only 3 patterning process steps. A piezoelectric plate working at the frequency range from 0.1 kHz to 2 kHz is bonded on to the back side of the silicon membrane to create the membrane actuation. The patterning process of thick photoresist used as the adhesive layer for the substrate bonding is also discussed in detail. The fluid flow is observed and the process reproducibility is proven which show a good prospect for the future development of miniaturized valveless pump for biomedical application.

Abstract: The current paper endeavors to present the design, fabrication, and test of a novel valveless piezoelectrically actuated micropump. The proposed micropump mainly comprises a stainless-steel structured chamber with a piezoelectric (PZT) diaphragm as a driving source to propel liquid stream under actuation. During tests, the micropump, operating at the frequency of 250 Hz and the voltage of 160 Vpp, engendered a mean water flowrate up to 0.779 ml/min. In the analysis, the computational fluid dynamics (CFD) software ACE+® was utilized to examine the time-varying flow phenomenon in a full-scale PZT micropump throughout an actuation cycle. The computational approach adopted the transient three-dimensional conservation equations of mass and momentum with the moving boundary specified to represent the movement of the diaphragm. At the frequency ranging from 150 to 250 Hz, the vortex pairs were evidently formed and thereby caused a relatively high pressure drop near the diffuser outlet inside the micropump chamber. Numerical experiments were also carried out by varying the opening angle of the diffuser/nozzle module within the range of 8°－12°, the angle setting of 8° can provide the best performance in term of the maximum pumping flowrate achieved.

Abstract: In order to predict the dynamic characteristics, the piezoelectric valve-less diffuser micropump is equivalent to the hydraulic model which consists of several hydraulic components. Using finite element analysis (FEA) method, the static analysis and the natural frequency calculation of the diaphragm are carried out. The mathematical model and the simulation method using AMESim are developed. Simulation results show the pressure and flow rate characteristics of the micropump, as well as the diaphragm stiffness influence. The agreement between the simulation results and those published previously indicates that the method combining FEA with the hydraulic analogue model provides a relatively simple and effective tool to study the dynamic characteristics of micropumps.

Abstract: This paper presents a design and performance evaluation of a valveless micropump fabricated from polydimethylsiloxane (PDMS) based on molding techniques. A circular lightweight piezo-composite actuator (LIPCA) was successfully developed for the actuating diaphragm of the micropump. The LIPCA is a composite actuator designed and fabricated with piezoceramics in combination with carbon fabric and glass epoxy. Numerical and experimental methods were used to investigate the performance of the circular LIPCA. The LIPCA was glued to a PDMS membrane to form the diaphragm of the micropump. The diaphragm has several advantages, such as high displacement, dome-shaped deformation and geometrically independent actuation profile. The diaphragm based on a LIPCA 9 mm in diameter produces a deflection of 27 μm at the applied voltage of ± 200 V and a frequency of 1 Hz. The micropump has a maximum water flow rate of 0.95 ml/min and a maximum backpressure of 3.8 kPa. The merits of the present micropump are low cost, ease of manufacturing and high level of effectiveness. The proposed LIPCA is proven to be a promising alternative to the conventional piezoelectric actuator used in micropumps.