一种模拟气液相变过程的相变模型

提出了一种基于VOF（volume of fluid）方法的相变模型，用于计算气液相变过程的控制方程中的传热传质源项。在单位时间步长上相界面附近发生的传热以瞬态热扩散来考虑，并假设该传热导致了相变的发生。相变模型能够通过相界面单元的温度、流体热物性以及时间步长来计算传热传质源项。通过一维Stefan问题和二维水平膜沸腾问题对该相变模型进行验证，对比了相界面位置以及温度分布，结果与理论解吻合良好。进一步探讨了相变模型中的时间步长对计算精度的影响。结果表明时间步长越小，本相变模型模拟得到的结果与理论解的偏差越小。

A phase change model for simulation of vapor-liquid phase change process

A new phase change model based on VOF (volume of fluid) method is proposed to calculate the energy and mass source terms in the equations describing the vapor-liquid phase change process. The heat transfer occurring near the interface is considered as a transient thermal diffusion process. The phase change model calculates the energy and mass source terms in terms of the temperature of the interfacial cell, thermal physical properties of gas and liquid phases, and the time step. One-dimension Stefan problem and two-dimension horizontal film boiling were adopted to verify this new phase change model. Simulation results of the interface position and temperature distribution agree well with analytical solutions. The effect of the time step on the simulation accuracy is discussed. The results show that the deviations between the simulation results and the theoretical results decrease with the decreasing time step.