Ejector Design

  • Giuseppe Grazzini
  • Adriano Milazzo
  • Federico Mazzelli


Ejector design may be performed at various levels of complexity. In many cases, ejectors are designed in a rather empirical way, and the only elements of the ejector geometry that receive a calculation effort are the main flow sections. Other elements, like the mixing zone length or the angle of the secondary flow inlet, are left to the experience of the designer. The effect of other details, like the presence of fillets between conical and cylindrical parts, is also neglected.

Indeed, a detailed analysis of the influence of geometrical details on the supersonic flow is not feasible with analytical tools. The only way to get a complete picture of the flow field is to analyze the ejector by a Computational Fluid Dynamics (CFD) approach. However, it must be stressed that CFD is not a design tool. The complete geometry of the ejector must be known in advance before any CFD analysis is attempted. Eventually, the design may be modified in order to mitigate any problem that could be revealed by the CFD results, but there is no way to state that all possible design options have been explored.

Probably, a hybrid approach combining a first scrutiny of possible configurations and a subsequent CFD analysis could be an answer. In the following sections, a few simple design tools will be presented, while the potential offered by up-to-date CFD techniques will be resumed in the following chapter.


Design Optimization Nozzle Diffuser Efficiency 


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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • Giuseppe Grazzini
    • 1
  • Adriano Milazzo
    • 1
  • Federico Mazzelli
    • 1
  1. 1.Department of Industrial EngineeringUniversity of FlorenceFlorenceItaly

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