Objective: Advances in microelectromechanical (MEMS) technologies over the past few decades have contributed to the rapid development of a wide range of microfluidic devices with different functionalities. Fluids are driven through microfluidic systems, therefore, in the current research, it is intended to parametrically investigate the effects of the main parameters, namely length, width and angle of attack of valves, piezoelectric length and applied voltage. Method: The approach of the present research is applied and analytical-experimental with numerical simulations where the tensile force is calculated using COMSOL Multiphysics software and the equations are calculated using the fully coupled algorithm in COMSOL Multiphysics. Findings: The results of the present research show that the main parameters significantly affect the performance of the designed micro pump. So that the applied voltage is 400 volts, the angle of attack is 45 degrees and the width of the valves is 6 micrometers, respectively for the piezoelectric length of 4, 2 and 5 mm, the flow rate is 6. 0.6, 9.6 and 16.6 microliters per minute are obtained. For valve widths of 6 and 8 micrometers, optimal attack angles of 60 and 65 degrees, the corresponding flow rates are 11.11 and 5.9 microliters per minute, respectively. Conclusion: Based on the results of the present research and the investigation of the behavior of the MICROPUMP and its output flow rate changes in different working conditions, as the length of the valves increases, the flow rate provided increases. Finally, there is a favorable condition for the width and angle of attack of the valves. This optimal width does not depend on the flow speed.

In this work, A 3-dimensional model is developed to investigate fluid flow in a magneto-hydrodynamic MICROPUMP. The equations are numerically solved using the finite volume method and the SIMPLE algorithm. This study analyzes the performance of the magnetohydrodynamic MICROPUMP. For this purpose, a magnetohydrodynamic MICROPUMP built in 2000, is simulated. The MICROPUMP has a channel with 20mm length, width of 800mm, height of 380mm and an electrode with 4mm length. The applied magnetic flux density was 13mT and the electric current was different for various solution (10-140 mA). The results show that the intensity of the magnetic field, the electric current and the geometry has an effect on the magnetohyrodynamic MICROPUMP performance. By increasing the amount of magnetic flux and electric current the average velocity increases. decreasing the channel length would increase the mean flow velocity. by increasing the channel depth, the mean flow velocity initially increases and then decreases, while at a depth of approximately 700-800mm the maximum averaged velocity will be resulted. The velocity increases by Increasing the channel width to 1500mm, however the velocity remained unchanged for larger values.

Recently, non-mechanical MICROPUMPs have become more appealing, due to their advantages in many areas such as electronics and medicine. In this research, a phase change MICROPUMP, as a novel type of nonmechanical MICROPUMP, has been investigated. Dimensionless parameters have been determined using dimensional analysis and a one dimensional steady model has been developed to describe the pumping mechanism and assess the working characteristics of the MICROPUMP. The results show that the theoretical model is in reasonable agreement with the experimental investigations. This analytical approach can be used in the design and fabrication of more efficient MICROPUMPs.

Continuous drug infusion plays an important role in drug effectiveness. However, in most cases, the size, weight, and power consumption of conventional pumps are among the most important factors that cause a lot of problems for patient comfort. The present work aims to design and optimize a Magnetohydrodynamic MICROPUMP for continuous drug infusion. A mathematical model of Magnetohydrodynamic micro pump is proposed and solved analytically to investigate its feasibility for drug infusion. For the patient's comfort, the MICROPUMP is optimized using non-dominated sorting genetic algorithm II. The number of channel rows and columns, channel height and width, and driving voltage are chosen as decision variables for multi-objective optimization. The Pareto front of the optimization result is presented. Six possible cases that meet the desired specifications are selected using a fuzzy decision-making approach. A computational fluid dynamic model is adopted to predict bubble formation due to the electrolysis phenomena. With higher reliability without any mechanical part, the present design can deliver drug flow 48 times while its driving voltage is 3 times lower than a conventional micro pump. In addition, it provides potentially better reliability and a simple fabrication process without any mechanical parts.

The liquid metal droplets in the mercury magnetic reciprocating MICROPUMP are actuated by Lorentz force and reciprocated inside some sub-channels. The droplets in sub-channel act as pistons to pump the working fluid. The initial step in establishing the performance of the mercury magnetic reciprocating MICROPUMPs is to study the motion of droplet inside the channel. The extraction of the analytic equation governing the droplet motion inside the channel is complicated due presence of electromagnetic fields and three dimensional effects of the flow. Further, the existence of a pumped fluid in contact with the droplet and the adhesion force due to small dimensions are considered as the other reasons. In this study, the forces operating on the droplet were figured out by the Lagrangian approach and lumped mass assumption for the droplet. Accordingly, forces less than 5% of the actuation force were eliminated from the motion equation of droplet employing dimensional analysis. The simplified equation was presented as an ordinary differential equation and solved numerically. In addition to the analytic solution, the issue was experimentally investigated for a case study. The analytic and empirical results accord well with one another. The method pointed out in this study can be applied to predict the droplet motion in various microsystems.

In the present work, a novel electromagnetic actuation flexible-valve MICROPUMP using the fluctuating elastic wall is proposed, based on one-way lymph transfer mechanism. A time dependent magnetic field is used for actuating the magnetorheological elastomer (contractible) wall. Two flexible valves are located in two terminals of microchannel in order to filter bidirectional flow and generate one-way fluid flow. Water properties are used for simulation and the maximum Reynolds number does not exceed 30 and Womersly number is lower than 1 in all cases. Knudsen number is much less than unity, therefore no-slip condition is valid at walls. A fully coupled magneto-fluid-solid interaction approach using time dependent study of two-dimensional incompressible fluid flow is performed. All solid parts follow Hook’s law and simulation is carried out using finite element approach by COMSOL Multiphysics software. A parametric study is conducted and the effect of key geometrical, structural and magnetical parameters have been examined on the net pumped volume. Present MICROPUMP is able to generate unidirectional flow and propel net volume of fluid left to right, and the net pumped volume of fluid is affected by design parameters. The proposed design can serve in a wide range of microfluidic applications, for example, flow rate and total mass transfer are completely controllable. At the end of the study, an optimum geometrical design based on initial model is proposed. The final design is able to transmit nearly two times the net volume compared to initial model and more than three times that of the previous design.

The Present article aims to design a piezoelectric MICROPUMP using a combinational form of microvalves with sufficient diodicity in low-pressure gradients. The goal is to enhance the capability of piezoelectric MICROPUMPs with Tesla-type valves in order to deliver insulin. Tesla-type valves are in the category of passive valves which have sufficient diodicity in case of high-pressure gradients. However, low mass flow rates are often required in drug delivery devices. In this paper, the performance of MT135 Tesla-type valve in low pressure-gradient flows has been investigated and a range of reunion angles, which have not been studied before has been examined by numerical solutions. Inspired by nozzle-diffuser valve types, some changes in the bypass path of the microvalve have been exerted to boost the diodicity of the valve in low-pressure conditions that resulted in 9. 97% increase of diodicity. At last but not least, the velocity gradients in singlephase flow of water has been attained and performance of MICROPUMP toward other kinds of flows has been investigated by a volume of fluid (VOF) model including water as the primary phase and air as the secondary one. To complete the analysis, a VOF model consisting of an arbitrary kind of Casson fluid with the primary phase of water was reached and discussed.