Ph.D Thesis

Ph.D StudentTzori Nimrod
SubjectPrinciples of a Micropump with Shape Memory Alloy
Membrane and Valves
DepartmentDepartment of Mechanical Engineering
Supervisor PROFESSOR EMERITUS Gad Hetsroni (Deceased)


The ongoing developments in the field of micromechanics are leading to realization of applications that one could only dream about a decade ago. One of the most important branches in micromechanics is the development of micro-flow systems.

In order to design and fabricate micro-flow systems, individual micro-flow components which provide both high performance and high reliability, must first be developed.

In this work we surveyed the work which have been done so far with regards to micropumps. We analyzed the reported micropumps and located their main drawbacks. Relying on this information we introduced a novel concept for a micropump which its membrane and valves are made of SMA thin films. The new micropump is based on the advantages which NiTi offers. The large strains which this material can undergo, accompanied with its shape memory properties, makes it the best choice for our application and enables us to achieve performances which are beyond the limits of the known competitor devices.

During this project we have introduced a comprehensive physical basis for our application. This physical layout provides a full set of equations which covers all the physical phenomena connected to our micropump. Since there is high conjugatin between these phenomena, there is no possibility of getting a full analytical solution to the proposed  set of equation. Therefore, we developed a simplified mecanical model which incorporates some constrains and assumptions which allow us to simplify the equations and to present a solvable model. From the analysis of the simplified mechanical model we chose a set of parameters which we found to be optimal for the realization of our proposed micropump. We used these parameters and have bulit a demonstration device. The demonstration device was used for the feasibility study in which we succeeded to perform shape setting to shape memory thin films, an achievement which has not been reported till now.