Design and development of PZT based micropump for microfluidic applications

Abstract

The present technical context is promptly growing in implementing onsite microfluidic utensils utilized in microfluidics owing to their great demand. The microfluidics mainly involves in implementing minuscule devices to deal with minute volumes of fluids. Manufacturing these microfluidic devices like micropumps is a great challenge and micropumps are very much indispensable to regulate and convey fluid in minute scale. In this research a PZT based micropump was designed and developed for microfluidic applications. A PZT actuated brass diaphragms and a comprehensive flow arrangement are the important elements of this micropump structure. Basically, the design prominences on a cross junction, engendered by a nozzle jet with a pump chamber and two inlet and an outlet channel respectively. In this sense, the fluid flow rectification is done by nozzle jet feature to expedite the fluid path within the system during every vibration cycle of PZT diaphragm. This micropump device was developed with layer by layer fabrication of polymethyl methacrylate (PMMA) plates using laser cutters and all the layers were squeezed in to attain required structure. In order to recognize the physiognomies of flow and to verify the experimental outcomes with simulated data, numerical simulation analysis in ANSYS were carried out. In addition, the PZT diaphragms were under taken for eigenfrequency study analysis in COMSOL Multiphysics as well. In this sense, the applied frequency of the piezoelectric diaphragms was varied by using the prescribed control system developed for this device. As per the test results, the maximum flow rate of 31.15 ml/min achieved at the frequency of 100 Hz. In addition, the thin film deposition techniques and the thermo elastic damping analysis on PZT actuators were also analyzed to identify the performance enhancement of this micropump. Since monitoring pressure and getting response is vital in microfluidic devices, design and simulation of MEMS based piezoresistive pressure sensor has been carried out. According to the piezoresistive structural coupled field analysis, the optimal diaphragm structure was chosen among three kinds of diaphragms considered for this study. Further, the thermo mechanical behavior of piezoresistive pressure sensors have also been considered in this research. At last, the complete numerical simulation was done for the micropump fluid flow coupled with the designed pressure sensor. According to this analysis, the pressure sensor gives the favorable sensitivity variation over micropump discharge pressure. Hence the developed micropump is not only for a specific application but also worthwhile in a wide range of microfluidic applications.