基于DFT和GCMC方法的MgCl_(2)水合盐储热材料吸水特性的数值模拟  

Numerical Simulation of Water Absorption Characteristics of MgCl_(2) Hydrated Salt Heat Storage Materials Based on DFT and GCMC Methods

作　　者：钱增辉 朱传勇 段欣悦[1] 姜枭 巩亮[1] QIAN Zenghui;ZHU Chuanyong;DUAN Xinyue;JIANG Xiao;GONG Liang(School of New Energy,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]中国石油大学(华东)新能源学院,青岛266580

出　　处：《工程热物理学报》2025年第4期1329-1336,共8页Journal of Engineering Thermophysics

基　　金：中央高校基本科研业务费(No.22CX06027A)。

摘　　要：MgCl_(2)水合盐被视为最具前景的中低温储热材料之一。研究MgCl_(2)水合盐储热材料微尺度下孔隙内的水分子吸附规律,揭示内在传质机理,对高效热化学储热系统的设计具有重要价值。本文基于DFT方法,研究了水分子在MgCl_(2)晶体表面吸附稳定后的分子几何构型,揭示了其可能的吸附位点。研究结果表明:水分子的吸附破坏了MgCl_(2)表面晶体规则的原子排列,这可能为后续进一步吸附和潮解创造了条件。此外,基于GCMC方法,研究了不同温度下,不同尺寸MgCl_(2)孔隙内水分子的吸附等温曲线和水分子浓度分布,结果表明:温度和孔隙尺寸对MgCl_(2)的吸水性有着明显的影响,当温度大于473 K时,孔隙的大小不再影响其吸水性能。MgCl_(2) hydrate salts are regarded as one of the most promising medium and low tem-perature heat storage materials.It is of great value for the design of efficient thermochemical heat storage systems to study the adsorption of water molecules in the pores of MgCl_(2) hydrated salt heat storage materials at the microscale and reveal the intrinsic mass transfer mechanism.In this paper,the molecular geometry of water molecules after adsorption stability on the surface of MgCl_(2) crystals was studied based on the DFT method,and the possible adsorption sites were revealed.The results show that the adsorption of water molecules destroys the regular atomic arrangement of the crystal on the surface of MgCl_(2),which may create conditions for further adsorption and deliquescent in the future.In addition,based on the GCMC method,the adsorption isothermal curves and concentra-tion distribution of water molecules in the pores of MgCl_(2) of different sizes at different temperatures were studied.The results show that temperature and pore size have a significant effect on the water absorption of MgCl_(2).When the temperature is greater than 473 K,the size of the pores no longer affects its water absorption performance.

关 键 词：热化学储能 MgCl2水合盐 DTF 水分子吸附 

分 类 号：TK123[动力工程及工程热物理—工程热物理]