Analytical and Experimental Methods of Design for Supersonic Two-Stage Ejectors

In this paper the supersonic ejectors are experimentally and analytically studied. Ejector is a device that uses the energy of a fluid to move another fluid. This device works like a vacuum pump without usage of piston, rotor or any other moving component. An ejector contains an active nozzle, a passive nozzle, a mixing chamber and a diffuser. Since the fluid viscosity is large, and the flow is turbulent and three dimensional in the mixing chamber, the numerical methods consume long time and high cost to analyze the flow in ejectors. Therefore this paper presents a simple analytical method that is based on the precise governing equations in fluid mechanics. According to achieved analytical relations, a computer code has been prepared to analyze the flow in different components of the ejector. An experiment has been performed in supersonic regime 1.5<M<2 and pressure and velocity have been measured in different parts of ejectors. Finally the analytical and experimental results have been compared. It is seen that the results have a reasonable accordance. Keywords—Ejector, Wind Tunnel, Supersonic, Diffuser, Mach number, Mixing Chamber