基于两相流EWF模型的样品表面相变行为及液膜变化的CFD预测

提出了一种利用两相流Eulerian Wall Film ( EWF)模型和自定义结露量公式相结合来预测样品表面相变行为及液膜变化的方法。首先利用自搭建环境实验箱开展结露物理实验,并分别基于两相流EWF模型与单相流模型进行仿真实验。结果表明,相对于单相流模型,EWF模型因考虑了相变过程而能够更加精确地模拟样品表面相变行为。然后通过自定义公式计算所得结露量与实测结露量的对比,验证了所提出结露量公式的正确性。最后在模拟与实测的温湿度曲线以及结露量吻合较好的前提下,模拟了样品表面液膜变化过程,过程中液膜呈现的形态与物理实验中原位摄像系统捕捉到的液膜形态初步吻合。

CFD prediction of phase change behavior and liquid film evolution on specimens based on the Eulerian wall film model of two-phase flow

ABSTRACT A method was presented to predict phase change behavior and liquid film evolution on specimens by combining the Eulerian wall film ( EWF) model of two-phase flow with the self-defined formula of dew amount. Firstly, a self-built environmental test chamber was used to carry out condensation physical tests, and simulated tests were respectively performed based on the EWF model and the single-phase flow model. It is found that the EWF model is more accurate than the single-phase flow model due to necessary consideration of the phase change process. Then, a self-defined formula was established to calculate the dew amount and it was verified by the physical tests. Finally, under the premise that simulated and tested temperatures, relatively humidity curves and dew amounts show good agreement, the changing process of liquid films on specimen surfaces was predicted, and the simulation prediction of liquid film shape on specimen surfaces is in consistent with in-situ video imaging morphology during the physical tests.