The influence of operating conditions and working fluids over ejector efficiencies: a CFD study

This paper investigates the influence of operating conditions and working fluids over ejector component efficiencies using an axi-symmetric Computational Fluid-Dynamics (CFD) model. This paper is focused on the case of a convergent nozzle ejector and is divided into two parts. In the first part, the CFD model is presented and is used for investigating ejector flow field in a wide range of operating conditions. In this part, air is the working fluid. In the second part, the local flow phenomena and their influence over ejector component efficiencies are investigated. Firstly, the CFD approach is used to determine the efficiencies of the ejector primary nozzle, suction chamber, mixing zone and diffuser. Secondly, efficiency maps and regressing equation linking efficiencies and local flow quantities are proposed and discussed. Finally, the influence of working fluid over ejector efficiencies is discussed and the case of Hydrogen as working fluid is presented.