中文摘要：

为研究吸收式制冷机常用工质对氨水溶液的微观形态，采用分子动力学方法：蛙跳法积分运动方程，Ewald加和方法计算库仑相互作用，分别对不同摩尔浓度的氨水溶液的汽液界面的微观结构、密度分布、界面厚度、界面张力进行了分析与计算，并拟合出界面厚度随氨水溶液摩尔浓度变化的线性关系式。结果表明：氨分子比水分子更容易吸附于汽液界面处，随着氨水溶液摩尔浓度的增加，汽液界面厚度增加，汽液界面张力减小，变化趋势与实验一致。界面张力的计算值从计算结果的量级和数量上看，与实验值接近。

英文摘要：

Molecular dynamics simulations （MD） were carried out to investigate the microstructure, longitudinal density profile, interface thickness and interface tension of the liquid-vapor interface of ammonia-water mixture with various concentration of ammonia as a working fluid commonly used in absorption refrigerator. The MD method makes use of leap-frog algorithm to solve the equations of motion and Ewald summation method to calculate the long-range interactions. The linear function formula between interface thickness and the mole fraction of ammonia is given in the present work. The simulation results show that ammonia tends to concentrate at the interface; the interface tension decreases and the interface thickness increases with the increase of the mole fraction of ammonia. The computed interface tension is consistent with experimental measurements from numerical magnitude.