介孔尺度及结构对混合硝酸盐热输运特性的影响  

Influence of mesoporous size and structure on heat transport characteristics of mixed nitrate

作　　者：何卓亚 杨启容[1] 李昭莹 毛蕊 王力伟 闫晨宣 He Zhuo-Ya;Yang Qi-Rong;Li Zhao-Ying;Mao Rui;Wang Li-Wei;Yan Chen-Xuan(College of Mechanical and Electrical Engineering,Qingdao University,Qingdao 266071,China)

机构地区：[1]青岛大学机电工程学院,青岛266071

出　　处：《物理学报》2022年第3期59-71,共13页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51701102)资助的课题。

摘　　要：采用分子动力学方法模拟介孔尺度和结构对混合硝酸盐热输运特性的影响.使用Material Studio软件分别建立不同尺度、两种结构的混合硝酸盐模型以及达到共晶状态的不同比例的NaNO_(3)-KNO_(3)模型,通过对模型进行运算并整理计算结果,对纳米尺度下混合硝酸盐热输运特性的微观机理进行分析.结果表明:太阳盐的相变温度随着纳米孔尺度的增大呈现先增加后减小的趋势,最终与宏观尺度下的熔点一致;阳离子的比例对混合硝酸盐的相变温度有很大的影响,且纳米线结构也会改变硝酸盐的相变温度.硝酸盐的体热膨胀系数随着介孔尺度的增大而减小,随着NaNO_(3)含量的增加而增大,随着介孔结构的改变而改变.离子之间的相互作用的增强会使导热率增大,但对定压比热容没有太大影响.Molecular dynamics method is used to simulate the influence of the mesopore size and structure on the heat transport characteristics of the mixed nitrate.The Material Studio software is used to establish the mixed nitrate models of different scales and two structures,and the NaNO_(3)-KNO_(3) models of different proportions that reach the eutectic state.By calculating the models and sorting out the calculation results,the phase transition of mixed nitrates on a nanometer scale is calculated and the micro-mechanism of heat transport characteristics is analyzed.The results show that the phase transition temperature of the solar salt first increases and then decreases with the increase of the nanopore size,and finally is consistent with the melting point on a macro scale.The proportion of cations has a great influence on the phase transition temperature of mixed nitrate,and the nanowire structures also change the phase transition temperature of nitrate.The bulk thermal expansion coefficient of nitrate decreases with the increase of mesoporous size,increases with the increase of NaNO_(3) content,and changes with the mesoporous structure.The enhancement of the interaction between ions will increase the thermal conductivity,but it will not have much effect on the specific heat capacity at a constant pressure.

关 键 词：混合硝酸盐 尺度 结构 热输运特性 

分 类 号：TQ126.25[化学工程—无机化工]