Papers by Keyword: Valveless

Abstract: This research work aims to identify the characteristic of flow in valveless impedance pump which uses acoustic impedance mismatch to drive flow. The experimental setup mainly focuses on the elastic section connected between two ends of rigid tube. Fluid flow rate resulting from the pumping mechanism were measured at different supply voltage. Meanwhile, the volume flow rate (ml / min) in the elastic tube section were also determined based upon different pinch location and width using water as a working fluid. In order to achieve these parameters quantification, the experimental test rig was designed and the set of equipments were successfully assembled. Then, the measured parameters resulting from the experiment of the impedance pump are presented in significant findings of four curves plots. It is found that the maximum flow rate occurred at voltage setting equal to 4 V. Significantly, results obtained could beneficial future design as a mimics model for novel Ventricular Assist Device use in cardiac patient as well as further explanation about the factor that influence the characteristic of valveless impedance pump.

Abstract: An investigation of flow in valveless micropumps is presented. Numerical simulations are done using ANSYS. It is found that both laminar flow and turbulence phenomena would occurs in the diffuser/nozzle element. And SST (shear stress transport) turbulence model is chosen to be the most appropriate turbulence model,The simulations show when the opening angel gets bigger, the flow in the micropump, especially in the diffuser/nozzle becomes unsteady. When separation flow of fluid appears, pressure loss coefficient decreases rapidly.

Abstract: This paper summarises a study which aims to develop and analyze the performance of the valveless impedance pump. Mechanism of valveless impedance pump is to apply acoustic impedance mismatch in order to drive the flow and also consists of a flexible connection at the ends to the more rigid sections. Characteristics of liquid velocity and pressure at the pump base valveless impedance at various supply voltage and different frequencies have been discovered through experimentation. Secondly, this research also aims to discuss the effect volume flow rate (millitres / min) in the elastic tube impedance based on different parameters of the pump pinch. The variation of pinch location and pinch width are also available through the results of this study. This study begins with the design set up to use the software and followed by installing all equipment used for the experiments. Then, this study continues to get results and make an analysis of the impedance pump by experimentation. Results found that all the parameters used in this experiment affect the flow rate in the impedance pump. Additional experiments on the effect of the thickness of the flexible tube on the flow rate gave lower values when the flexible tube is relatively thicker.

Abstract: This paper presents the fabrication and preliminary experimental studies of flow performance on a valveless micro impedance pump actuated by the shear mode PZT actuator, a novel method of pumping fluid on the microscale. The micro impedance pump was constructed of three nickel electroforming components, two glass tubes, a PZT actuator and a glass substrate. The three electroforming components include a bottom structure plate, a channel plate and a top structure plate. The AZ-type positive photoresist was used as the electroforming mould, which was patterned by UV lithography. The top and bottom structure plates were aligned and assembled with the channel plate by epoxy adhesive such that a micro channel with a compressible section coupled at both ends to rigid sections of different impedance was formed. A pressure head can be built up to drive flow through the accumulative effects of wave propagation and reflection originating from the periodic PZT excitation, located asymmetrically along the length of the compressible section of the channel. Experimental results showed that the flow was reversible and pressure heads had a highly non-linear dependence on the frequency and amplitude of the excitation. Maximum flow rates of 13 μl min-1 have been achieved with the channel size of 15μm high and 4 mm wide.