Three types of one-sided actuating piezoelectric micropumps are studied in this paper. In the first type, one-sided actuating micropump with two check valves can enhance the flow rate and prevent the back flow in suction mode to keep the flow in one direction. Furthermore, the frequency modulator is applied in the micropump to adjust and promote the maximum flow rate higher than 5.0？mL/s. In the second type, valveless micropump with secondary chamber shows that the secondary chamber plays a key role in the application of the valveless micropump. It not only keeps the flow in one direction but also makes the flow rate of the pump reach 0.989？mL/s. In addition, when a nozzle/diffuser element is used in valveless micropump, the flow rate can be further improved to 1.183？mL/s at a frequency of 150？Hz. In the third type, piezoelectric actuating pump is regarded as an air pump in the application of a microfuel cell system, which can increase more air inlet to improve the fuel/air reaction and further increase the performance of fuel cell. 1. Introduction In recent years, micropump plays a significant role in many fields, specifically in chemical, medical, and thermal managements. Since there are distinct requirements in each field, several types of micropumps have been designed to meet those requirements. Micropumps, which have the advantage of small size and configurable dimension, are gradually becoming one of the solutions for electronic heat dissipation. There are several types of actuation approaches in developing, such as electromagnetic [1, 2], piezoelectric [3, 4], shape memory alloy [5], electrostatic [6], and thermopneumatic [7] devices. Most of actuations are complicated in structure and have great energy consumption. However, piezoelectric actuation has the notable advantages that are a relatively simple component and energy consumption. Micropumps can be categorized into two major types: displacement pumps [8–10] and dynamic pumps [11, 12]. Displacement pumps use the moving mechanical part to change the volume of the chamber, such as the one-sided actuating diaphragm pumps. Dynamic pumps usually utilize the interactions of the fluid with an electric or magnetic field, which continuously applies force on working fluid. Electrohydrodynamic [11] and magnetohydrodynamic [12] are the examples of dynamic pump. Considering flow direction elements, micropumps can be classified as with or without valves. The first prototype of a valveless pump consisting of a circular cylindrical volume where the top had a thin brass diaphragm to which a piezoelectric
References
[1]
S. B？hm, W. Olthuis, and P. Bergveld, “A plastic micropump constructed with conventional techniques and materials,” Sensors and Actuators A, vol. 77, no. 3, pp. 223–228, 1999.
[2]
C. Yamahata, F. Lacharme, Y. Burri, and M. A. M. Gijs, “A ball valve micropump in glass fabricated by powder blasting,” Sensors and Actuators B, vol. 110, no. 1, pp. 1–7, 2005.
[3]
E. Stemme and G. Stemme, “A valveless diffuser/nozzle-based fluid pump,” Sensors and Actuators A, vol. 39, no. 2, pp. 159–167, 1993.
[4]
A. Olsson, G. Stemme, and E. Stemme, “Diffuser-element design investigation for valve-less pumps,” Sensors and Actuators A, vol. 57, no. 2, pp. 137–143, 1996.
[5]
W. L. Benard, H. Kahn, A. H. Heuer, and M. A. Huff, “Thin-film shape-memory alloy actuated micropumps,” Journal of Microelectromechanical Systems, vol. 7, no. 2, pp. 245–251, 1998.
[6]
O. Francais, I. Dufour, and E. Sarraute, “Analytical static modelling and optimization of electrostatic micropumps,” Journal of Micromechanics and Microengineering, vol. 7, no. 3, pp. 183–185, 1997.
[7]
A. Wego, H.-W. Glock, L. Pagel, and S. Richter, “Investigations on thermo-pneumatic volume actuators based on PCB technology,” Sensors and Actuators A, vol. 93, no. 2, pp. 95–102, 2001.
[8]
C. R. de Lima, S. L. Vatanabe, A. Choi, P. H. Nakasone, R. F. Pires, and E. C. Nelli Silva, “A biomimetic piezoelectric pump: computational and experimental characterization,” Sensors and Actuators A, vol. 152, no. 1, pp. 110–118, 2009.
[9]
J. Kan, K. Tang, G. Liu, G. Zhu, and C. Shao, “Development of serial-connection piezoelectric pumps,” Sensors and Actuators A, vol. 144, no. 2, pp. 321–327, 2008.
[10]
P. Skafte-Pedersen, D. Sabourin, M. Dufva, and D. Snakenborg, “Multi-channel peristaltic pump for microfluidic applications featuring monolithic PDMS inlay,” Lab on a Chip, vol. 9, no. 20, pp. 3003–3006, 2009.
[11]
M. Holtappels, M. Stubbe, and J. Gimsa, “Ac-field-induced fluid pumping in microsystems with asymmetric temperature gradients,” Physical Review E, vol. 79, no. 2, Article ID 026309, 10 pages, 2009.
[12]
E.-G. Kim, J.-G. Oh, and B. Choi, “A study on the development of a continuous peristaltic micropump using magnetic fluids,” Sensors and Actuators A, vol. 128, no. 1, pp. 43–51, 2006.
[13]
H. K. Ma, B. R. Hou, H. Y. Wu, C. Y. Lin, J. J. Gao, and M. C. Kou, “Development and application of a diaphragm micro-pump with piezoelectric device,” Microsystem Technologies, vol. 14, no. 7, pp. 1001–1007, 2008.
[14]
H.-K. Ma, B.-R. Hou, C.-Y. Lin, and J.-J. Gao, “The improved performance of one-side actuating diaphragm micropump for a liquid cooling system,” International Communications in Heat and Mass Transfer, vol. 35, no. 8, pp. 957–966, 2008.
[15]
H.-K. Ma, B.-R. Chen, J.-J. Gao, and C.-Y. Lin, “Development of an OAPCP-micropump liquid cooling system in a laptop,” International Communications in Heat and Mass Transfer, vol. 36, no. 3, pp. 225–232, 2009.
[16]
H. K. Ma, H. C. Su, and J. Y. Wu, “Study of an innovative one-sided actuating piezoelectric valveless micropump with a secondary chamber,” Sensors and Actuators A, vol. 171, no. 2, pp. 297–305, 2011.
[17]
J. Kan, Z. Yang, T. Peng, G. Cheng, and B. Wu, “Design and test of a high-performance piezoelectric micropump for drug delivery,” Sensors and Actuators A, vol. 121, no. 1, pp. 156–161, 2005.
[18]
J. M. Gere, Mechanics of Materials, Brooks Cole, Pacific Grove, Calif, USA, 5th edition, 2001.
[19]
L. D. Landau and E. M. Lifshitz, Theory of Elasticity, Pergamon, Oxford, UK, 1986.
[20]
W.-J. Sheu, R.-T. Huang, and C.-C. Wang, “Influence of bonding glues on the vibration of piezoelectric fans,” Sensors and Actuators A, vol. 148, no. 1, pp. 115–121, 2008.
[21]
L. S. Pan, T. Y. Ng, X. H. Wu, and H. P. Lee, “Analysis of valveless micropumps with inertial effects,” Journal of Micromechanics and Microengineering, vol. 13, no. 3, pp. 390–399, 2003.
[22]
L. S. Pan, T. Y. Ng, G. R. Liu, K. Y. Lam, and T. Y. Jiang, “Analytical solutions for the dynamic analysis of a valveless micropump—a fluid-membrane coupling study,” Sensors and Actuators A, vol. 93, no. 2, pp. 173–181, 2001.
[23]
V. Ziebart, O. Paul, U. Münch, J. Schwizer, and H. Baltes, “Mechanical properties of thin films from the load deflection of long clamped plates,” Journal of Microelectromechanical Systems, vol. 7, no. 3, pp. 320–328, 1998.
[24]
A. Ullmann, “The piezoelectric valve-less pump—performance enhancement analysis,” Sensors and Actuators A, vol. 69, no. 1, pp. 97–105, 1998.
[25]
S. S. Rao, Mechanical Vibrations, Pearson Prentice Hall, New Jersey, NJ, USA, 4th edition, 2004.
[26]
Y. C. Hsiao, Numerical analysis of a valveless One-side actuating piezoelectric micopup [M.S. thesis], National Taiwan University, Taipei, Taiwan, 2009.
[27]
H.-K. Ma, S.-H. Huang, J.-S. Wang, C.-G. Hou, C.-C. Yu, and B.-R. Chen, “Experimental study of a novel piezoelectric proton exchange membrane fuel cell with nozzle and diffuser,” Journal of Power Sources, vol. 195, no. 5, pp. 1393–1400, 2010.
[28]
H.-K. Ma, J.-S. Wang, and Y.-T. Chang, “Development of a novel pseudo bipolar piezoelectric proton exchange membrane fuel cell with nozzle and diffuser,” Journal of Power Sources, vol. 196, no. 8, pp. 3766–3772, 2011.
[29]
H.-K. Ma, J.-S. Wang, W.-H. Su, and W.-Y. Cheng, “The performance of a novel pseudo-bipolar bi-cell piezoelectric proton exchange membrane fuel cell with a smaller nozzle and diffuser,” Journal of Power Sources, vol. 196, no. 18, pp. 7564–7571, 2011.
