Cao Xiaolin, Zeng Wei, Chen Hui, et al. Numerical Analysis of Refrigerant/Oil Mixture in a Vertical U-tube[J]. Journal of refrigeration, 2012, (1).
DOI:
Cao Xiaolin, Zeng Wei, Chen Hui, et al. Numerical Analysis of Refrigerant/Oil Mixture in a Vertical U-tube[J]. Journal of refrigeration, 2012, (1). DOI: 10.3969/j.issn.0253-4339.2012.01.046.
Numerical Analysis of Refrigerant/Oil Mixture in a Vertical U-tube
EES software was used to simulate the flow of refrigerant and oil in underground U-tube of the Direct Expansion Ground Source Heat Pump. The results show that: the pressure of refrigerant/oil mixture first increases and then decreases along the U-tube;the temperature of refrigerant/oil mixture increases firstly and then decreases
in superheat region
the temperature rises sharply; the refrigerant/oil mixture exits in U-tube mainly as annular flow; the minimum refrigerant/oil return velocity is increasing when the U-tube diameter increases; comparing the simulation results with the experimental results find that the oil in the U-tube of the experimental system can return normally.