Journal of Shanghai Jiaotong University ›› 2019, Vol. 53 ›› Issue (7): 860-865.doi: 10.16183/j.cnki.jsjtu.2019.07.013

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A Numerical Model of the Two-Phase CO2 Ejectors

WANG Yufeng 1,WANG Dandong 1,HU Jichao 1,CHEN Liang 1,CHEN Jiangping 1,2   

  1. 1. Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200240, China; 2. Shanghai High Efficiency Cooling System Research Center, Shanghai 200240, China
  • Online:2019-07-28 Published:2019-08-02

Abstract: A CFD-based numerical analysis of a two-phase R744 ejector using heterogeneous mixture model is presented in this work. The flow patterns inside the ejector, such as the mass transfer rate, change of pressure and velocity alongside the ejector are analyzed. Based on the experimental work, the numerical model is validated. The effect of the ejector’s nozzle geometry on the ejector performance is discussed, and an optimization of the nozzle geometry is performed. Based on the experimental data, the numerical model predicts the motive mass flow rate and the suction pressure within an error margin of 6.5%. Shock wave phenomenon can be observed around the nozzle exit. The motive mass flow rate of the ejector decreases and the motive velocity increases with the increasing divergent length. The optimization of the nozzle geometry can increase the ejector efficiency by 10.5%.

Key words: ejector; structure optimization; carbon dioxide; two-phase flow; flow field characteristic

CLC Number: