Chandra Anirban, Keblinski Pawel
Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
Department of Material Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
J Chem Phys. 2020 Sep 28;153(12):124505. doi: 10.1063/5.0018726.
Recently, molecular dynamics (MD) simulations were utilized to show that Schrage theory predicts evaporation/condensation mass fluxes with good accuracy in the case of monoatomic and non-polar molecular fluids. Here, we examine if they are equally accurate for molecular polar fluids, such as water. In particular, using molecular dynamics (MD) simulations, we study the steady state evaporation/condensation processes of water in a one-dimensional heat-pipe geometry to ascertain the validity of Schrage relationships. Non-equilibrium mass flow is driven by controlling the temperatures of the source/sink. Equilibrium simulations are utilized to evaluate the saturation properties and the mass accommodation coefficients as a function of temperature. Our results indicate that Schrage equations predict the evaporation/condensation rates of water with good accuracy. Moreover, we show that molecular velocity distributions in the vapor phase are indeed Maxwellian distributions shifted by the velocity of the macroscopic vapor flow, as assumed in Schrage's theoretical analysis.
最近，分子动力学（MD）模拟被用于表明，在单原子和非极性分子流体的情况下，施拉格理论能相当准确地预测蒸发/冷凝质量通量。在此，我们研究该理论对于诸如水等分子极性流体是否同样准确。具体而言，通过分子动力学（MD）模拟，我们研究一维热管几何结构中水分子的稳态蒸发/冷凝过程，以确定施拉格关系式的有效性。通过控制源/汇的温度来驱动非平衡质量流。利用平衡模拟来评估饱和性质以及作为温度函数的质量适应系数。我们的结果表明，施拉格方程能相当准确地预测水的蒸发/冷凝速率。此外，正如施拉格理论分析中所假设的那样，我们表明气相中的分子速度分布确实是由宏观蒸气流速度偏移的麦克斯韦分布。
