Design And Dynamic Analysis Of Electrostatic Micropump

As an important branch of Micro-electro-mechanical-system (MEMS), Micro-fluid system is defined as technologies focus on controlling, manipulating and inspecting fluid under micro-scale. The Micropump as core part of the micro-fluid system is developed fast. Electrostatic Micropump is investigated theoretically widely and deeply in this thesis.Size effects are investigated; the size effects of quantum of micro-fluid are analyzed. The size effects of key quantum are given. The equivalent circuit of fixed-fixed beam is established using F-V analogy; the equivalent circuit of fluid is given. All of these are useful for researching MEMS devices.Using Elastic Plate Beading Theory and Parallel Plate Condenser Theory, the governing equation of membrane deformation was derived; the mathematical model of free vibration in membrane is established. The valve unit is analyzed. The mathematical models of flap valve in Micropump and diffuser/nozzle in valveless Micropump are established, the equations of flux and pressure of the Micropump is given. All of these are more important for Micropump design.The expressions of absolute value, relative value and sensitivity of size effect are established using functional analysis. The size effects in primary function are analyzed qualitatively. Effect of electrostatic force was analyzed. The formulae on calculation the driving force is given. The size effect of electrostatic force is analyzed using functional analysis. Faster respond and high power density of electrostatic force in MEMS device are testified. The pull-in phenomenon is analyzed. The formula on calculation the pull-in voltage is established. The size effect of pull-in voltage was analyzed. After investigating the size effect of pull-in voltage, Sensitivity of parameters is given using functional analysis of pull-in voltage. For the Micropump with circular membrane, pull-in voltage is investigated. It is obtained that the electrode-membrane distance and membrane thickness display the positive size effect while the circular membrane radius displays the negative size effect. The effect of electrode-membrane distance is strong. It is the base in accurate control and design of electrostatic actuators in MEMSDynamic characteristic of Micropump is simulated using ANSYS software. Using FEM coupling, make sure that the displacement of membrane is in linear proportion with voltage.More voltage brings more displacement. And thinner membrane brings more volume change of chamber. The based frequency is also in linear proportion with thickness. The pressure and flux is simulated. The efficiency of micropump can be increased by increasing voltage, reducing thickness of membrane and making the Micropump working as based frequency. The equivalent circuit of membrane is analyzed. All of these are foundation of accurate control and design of Micropump.