Numerical Simulation of Heat Transfer During Boiling Flow of Cryogenic Fluid in Vertical Tube

摘要

The two-fluid model has been extensively used in modeling boiling flow of water, however, there are few equivalent studies of boiling flow of cryogenic liquids. In the present study the two-fluid model was implemented in the OpenFOAM source code by incorporating closure correlations, which more adjustable for cryogenic liquids. Then boiling flow of liquid nitrogen in a vertical tube was numerically simulated using the modified basic model. In order to include the boiling effect, several different subroutines which model evaporation and condensation phenomena were attached to the solver. Comparison with experimental data shows that the modified model is satisfactorily improved in accuracy. This study demonstrated that the following parameters and models are important for accurate prediction: the bubble diameter frequency departure, the bubble diameter distribution and the active site nucleation density, among which, the active site nucleation density has the most significant influence.