SⅡ型R134a水合物稳定性的分子动力学模拟  

Molecular dynamics simulation for the stability on SⅡ R134a hydrate

作　　者：袁争印 梁坤峰[1] 李盈盈[1] 贾雪迎 毛爱霞[2] 王林[3] 李健[1] 芮胜军[1] 董彬[1] Yuan Zhengyin Hang Kunfeng Li Yingying Jia Xueying Mao Aixia Wang Lin Li Jian Rui Shengjun Dong Bin(Institute of Refrigeration and Air Conditioning Technology, Henan University of Science and Technology, Luoyang 471003, China School of Physics and Engineering, Henan University of Science and Technology, Luoyang 471003, China School of Civil Engineering, Henan University of Science and Technology, Luoyang 471003, China)

机构地区：[1]河南科技大学制冷与空调技术研究所,洛阳471003 [2]河南科技大学物理工程学院,洛阳471003 [3]河南科技大学土木工程学院,洛阳471003

出　　处：《低温与超导》2017年第3期79-86,共8页Cryogenics and Superconductivity

基　　金：国家自然科学基金(U1304521);河南省高校科技创新人才支持计划(16HASTIT027);河南科技大学创新团队资助(2015XTD004)资助

摘　　要：SⅡ型R134a制冷剂笼状水合物是理想的蓄冷介质之一。基于分子动力学(MD)方法,建立晶体结构模型,在NPT系综下运算,通过观察最终构象,分析计算体系中粒子的均方位移(MSD)和径向分布函数(RDF),从微观上揭示了小分子和温度对SⅡ型水合物晶体结构稳定性的影响。结果表明:小分子对小晶穴(512)占有率从0.25变化到1.00,占有率为0.25和0.50时,水合物晶体结构分解严重,体系中分子混乱,晶体结构难以稳定存在,占有率在0.75以上时,水合物晶体结构清晰有序,能够稳定存在;当体系温度由260K增大到290K时,水合物结构的稳定性逐渐降低,在280K时晶体结构出现扭曲变形,此时有部分水合物开始分解。R134a refrigerant SⅡ clathrate hydrate is an ideal medium for accumulation of cold. Based on the molecular dynamics （MD） method, a crystal structure model was built and operated under the NPT ensemble. By observing the final conformation, the mean square displacement（MSD） and radial distribution function （RDF） of particles in the system were analysed, the affect of small molecules and temperature on the stability of the hydrate crystalline structure was revealed from the microscopic mechanism. Results indicate that the occupancy ratio of the small molecule to small crystal cavity （ 512 ） varies from 0.25 to 1.00. When the occupancy ratio is 0.25 and O. 50, the hydrate crystal structure decomposes gravely and the molecules in the system move chaotically, so the crystal structure is unstable. If the occupancy ratio is above 0.75, the hydrate crystal structure is so clear and orderly, the structure exists steadily. The hydrate structure stability reduces gradually when the temperature increases from 260 K to 290 K , the crystal structure at 280K distorts and hydrate starts to decompose partially.

关 键 词：蓄冷介质 稳定性 制冷剂水合物 SⅡ型 分子动力学(MD) 评价指标 

分 类 号：U463.851[机械工程—车辆工程]