Optimization of two-phase R600a ejector geometries using a non-equilibrium CFD model

Moon Soo Lee, Hoseong Lee, Yunho Hwang, Reinhard Radermacher, Hee Moon Jeong

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)


A vapor compression cycle, which is typically utilized for the heat pump, air conditioning and refrigeration systems, has inherent thermodynamic losses associated with expansion and compression processes. To minimize these losses and improve the energy efficiency of the vapor compression cycle, an ejector can be applied. However, due to the occurrence of complex physics i.e., non-equilibrium flashing compressible flow in the nozzle with possible shock interactions, it has not been feasible to model or optimize the design of a two-phase ejector. In this study, a homogeneous, non-equilibrium, two-phase flow computational fluid dynamics (CFD) model in a commercial code is used with an in-house empirical correlation for the mass transfer coefficient and real gas properties to perform a geometric optimization of a two-phase ejector. The model is first validated with experimental data of an ejector with R600a as the working fluid. After that, the design parameters of the ejector are optimized using multi-objective genetic algorithm (MOGA) based online approximation-assisted optimization (OAAO) approaches to find the maximum performance.

Original languageEnglish
Pages (from-to)272-282
Number of pages11
JournalApplied Thermal Engineering
Publication statusPublished - 2016 Oct 25

Bibliographical note

Funding Information:
This work was supported by the sponsors of the Center for Environmental Energy Engineering (CEEE), University of Maryland, College Park, MD, USA.

Publisher Copyright:
© 2016


  • Ejector
  • MOGA
  • OAAO
  • R600a
  • Two-phase CFD

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Industrial and Manufacturing Engineering


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