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Numerical Study on Two-Phase Flow of Transcritical CO2 in Ejector

  • Xu Feng
  • Zhenying ZhangEmail author
  • Jianjun Yang
  • Dingzhu Tian
Conference paper
  • 208 Downloads
Part of the Environmental Science and Engineering book series (ESE)

Abstract

The transcritical CO2 two-phase flow in the ejector was investigated numerically by the computational fluid dynamics (CFD) method. The accuracy of the built three-dimensional CFD model was validated by contrasting the simulating results with the available experimental data in the literature. The distribution of pressure, velocity and two-phase volume fraction inside the ejector was analyzed. The effect of the primary nozzle diverging angle on the performance of the ejector was obtained. The results showed that the pressure of the CO2 is decreased and the velocity is increased after the stream enters the primary nozzle. The velocity at the exit of the primary nozzle reaches a maximum value, which is about 168 m/s. The two streams are then mixed in the mixing chamber; the velocity and the pressure were found to be shocked initially and then tend to be stable. The velocity decreases and the pressure increases gradually in the diffuser section. The vaporization of the transcritical CO2 was found to be occurred near the throat of the primary nozzle. The optimum diffusion angle of the primary nozzle was found to be about 6°, where the mass entrainment ratio is 0.83.

Keywords

Ejector CO2 Numerical simulation Primary nozzle 

Notes

Acknowledgements

The project is supported by Scientific and Technological Research Projects of Universities in Hebei Province (ZD2017061), Hebei Province Construction Science and Technology Research Project (2017-131), supported by the Graduate Student Innovation Fund of North China University of Science and Technology (2019S21).

References

  1. 1.
    Zhang, Z., Tian, L.: Effect of suction nozzle pressure drop on the performance of an ejector-expansion transcritical CO2 refrigeration cycle. Entropy 16(8), 4309–4321 (2014)CrossRefGoogle Scholar
  2. 2.
    Liu, F., Li, Y., Groll, E.A.: Performance enhancement of CO2 air conditioner with a controllable ejector. Int. J. Refrig. 35(6), 1604–1616 (2012)CrossRefGoogle Scholar
  3. 3.
    Hu, J., Shi, J., Liang, Y., et al.: Numerical and experimental investigation on nozzle parameters for R410A ejector air conditioning system. Int. J. Refrig. 40, 338–346 (2014)CrossRefGoogle Scholar
  4. 4.
    Liu, F., et al.: Comprehensive experimental performance analyses of an ejector expansion transcritical CO2 system. Appl. Therm. Eng. 98, 1061–1069 (2016)CrossRefGoogle Scholar
  5. 5.
    Wang, F., Li, D.Y., Zhou, Y.: Analysis for the ejector used as expansion valve in vapour compression refrigeration cycle. Appl. Therm. Eng. 96(5), 576–582 (2016)CrossRefGoogle Scholar
  6. 6.
    Haida, M., et al.: Modified homogeneous relaxation model for the R744 transcritical flow in a two-phase ejector. Int. J. Refrig. 85, 314–333 (2018)CrossRefGoogle Scholar
  7. 7.
    Zhang, H., et al.: Influence investigation of friction on supersonic ejector performance. Int. J. Refrig. 85, 229–239 (2018)CrossRefGoogle Scholar
  8. 8.
    Zheng, L., Deng, J.: Research on CO2, ejector component efficiencies by experiment measurement and distributed-parameter modeling. Energy Convers. Manag. 142, 244–256 (2017)CrossRefGoogle Scholar
  9. 9.
    Baek, S., Song, S.: Numerical study for the design optimization of a two-phase ejector with R134a refrigerant. J. Mech. Sci. Technol. 32(9), 4231–4236 (2018)CrossRefGoogle Scholar
  10. 10.
    Taslimitaleghani, S., et al.: Modeling of two-phase transcritical CO2 ejectors for on-design and off-design conditions. Int. J. Refrig. 87, 91–105 (2018)CrossRefGoogle Scholar
  11. 11.
    Li, Y., et al.: Visualization of two-phase flow in primary nozzle of a transcritical CO2 ejector. Energy Convers. Manag. 171, 729–741 (2018)CrossRefGoogle Scholar
  12. 12.
    Nakagawa, M., Morimune, Y.: Subsequent report on nozzle efficiency of two-phase ejector used in carbon dioxide refrigerator. Therm. Sci. Eng. 11, 51–52 (2003)Google Scholar
  13. 13.
    Lawrence, N., Elbel, S.: Experimental and Analytical Investigation of Automotive Ejector Air-Conditioning Cycles Using Low-Pressure Refrigerants. International Refrigeration and Air Conditioning at Purdue, West Lafayette, USA (2012)Google Scholar
  14. 14.
    Wang, L., et al.: Numerical study on optimization of ejector primary nozzle geometries. Int. J. Refrig. 76, 219–229 (2017)CrossRefGoogle Scholar
  15. 15.
    Baek, S., et al.: Numerical study of high-speed two-phase ejector performance with R134a refrigerant. Int. J. Heat Mass Transf. 126, 1071–1082 (2018)CrossRefGoogle Scholar
  16. 16.
    Tang, B.: Study on Compression-Ejection Refrigeration System and Ejector. Zhengzhou University (2013)Google Scholar
  17. 17.
    Bilir Sag, N., et al.: Energetic and exergetic comparison of basic and ejector expander refrigeration systems operating under the same external conditions and cooling capacities. Energy Convers. Manag. 90, 184–194 (2015)CrossRefGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2020

Authors and Affiliations

  • Xu Feng
    • 1
  • Zhenying Zhang
    • 1
    Email author
  • Jianjun Yang
    • 1
  • Dingzhu Tian
    • 1
  1. 1.School of Architecture and Civil EngineeringNorth China University of Science and TechnologyTangshanChina

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