Investigation of Shear Forces using Coupled ANSYS Simulation of Micro Diaphragm Pump Dynamics

Micropumps are devices that transport, manipulate and control small volume fluids. The increasing interest in the field of micropump studies can be ascribed to the potential and capability of these devices to deliver an accurate dosage of fluids with high precision. To achieve high quality design of micropumps, it is necessary to understand the underlying concepts of these devices. There is every need for an efficient research work to be performed. Micropumps serve a wide range of applications from medical technology, industrial applications, cooling systems for microelectronics, and chemical analysis. In this thesis work, a 3D fluid-electro-mechanical coupled simulation of an ideal valve piezoelectrically actuated micropump is performed using ANSYS Workbench V19.0. The numerical model uses a 2-way fluid structure coupling to demonstrate fluid-structure interaction between the bottom surface of the membrane and working fluid by mapping the displacement data from the membrane to the fluid and force data from the fluid to the membranes bottom surface. A modified geometry of the micropump chamber is developed to eliminate the errors raised in mesh generation due to presence of thin volumes. Effects of input driving frequency on the flow rate, pressure-flow characteristics, and shear stresses occurring inside the chamber are evaluated. Using a peak-to-peak voltage of 80 V with the frequencies 1, 20, and 40 Hz, 2-way FSI simulation of micropump with ideal valves is carried out and it was found that the field variables such as flow velocities, pressure as well as volu me flow rate tend to increase with the increase in frequency. The fluid damping effect on the bottom surface of the membrane is seen slightly higher when frequency increases. The fluid flow is mainly observed to fall into laminar regime which was verified by an evaluation of Reynolds number.