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Modelling of CO2 transonic flashing flow through a convergent-divergent nozzle using novel closure equations in the Delayed Equilibrium Model.

Number: 0778

Author(s) : ANGIELCZYK W., BUTRYMOWICZ D., GAGAN J., SMIERCIEW K.

Summary

Due to the global concern for the natural environment, the use of natural refrigerants is increasing. European legislation restricts the use of refrigerants to fluids with a GWP lower than 150. Carbon dioxide meets this requirement. Unfortunately, the critical temperature of CO2 is relatively low. Thus, conventional subcritical Vapour Compression Refrigeration Device (VCRD) of CO2 has limited use, and the supercritical and transcritical VCRDs are energetically inefficient. One of the prospective solutions to this problem is the application of a two-phase ejector. The key element of the ejector is the motive nozzle, which correct design is crucial for the efficient operation of the ejector. Proper nozzle design requires an appropriate model describing the flow in the nozzle. The literature review revealed that the Delayed Equilibrium Model (DEM) is the most accurate. Consequently, this work presents closure equations of DEM developed for the transonic flashing flow of CO2, gives physical interpretations of simulation results of the model and discusses potential ways of its application in motive nozzle geometry optimisation.
The formulated DEM was subjected to experimental validation, which revealed that its predictions are more accurate than the prediction of the reference Homogeneous Equilibrium Models.

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Pages: 11 p.

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Details

  • Original title: Modelling of CO2 transonic flashing flow through a convergent-divergent nozzle using novel closure equations in the Delayed Equilibrium Model.
  • Record ID : 30031667
  • Languages: English
  • Subject: Technology
  • Source: Proceedings of the 26th IIR International Congress of Refrigeration: Paris , France, August 21-25, 2023.
  • Publication date: 2023/08/21
  • DOI: http://dx.doi.org/10.18462/iir.icr.2023.0778

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