Pouria Pakzad - Department of Renewable Energies and Environment, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
Saeed Almasifard - Department of Renewable Energies, Faculty of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran, Iran

Ejectors are devices used to suck secondary fluid using momentum transmission and energy from high primary jet velocities. Ejectors can work with incompressible fluids (liquids), commonly known as jet pumps or reducers. The term ejector and ejector are used for ejectors when they work with compressible fluids (gases and vapors). These events are accompanied by considerable thermodynamic complexity in the mixer and diffuser parts. Micro-dimensional multi-stage ejectors can reduce waste and increase the efficiency of some microelectromechanical electrical devices that require liquid pumping. In the present paper, using computational fluid dynamics technique, a study of various types of multi-stage ejectors, modeling, and simulation of multi-stage ejectors in micro dimensions by mathematical models has been performed. Another sub-goal of this research is to investigate the efficiency of multi-stage ejectors in micro dimensions. One of the important issues in this dissertation is modeling in micro dimensions. The fundamental equations are solved by Fluent commercial software. The obtained numerical results are compared with the existing analytical and experimental solution results, for which there is an acceptable agreement between them.

Multi-stage ejector, Micro ejector, CFD analysis, Optimum design