基于金属有机框架的汽油机冷启动碳氢化合物吸附和扩散性能的研究  

Molecular dynamics study on effects of different metal-organic frameworks hydrocarbon adsorption and diffusion behavior during gasoline engine cold start stage

作　　者：左青松[1] 翟润行 马颖[1] 谢永川 沈壮 陈伟[1] 朱国辉 ZUO Qingsong;ZHAI Runhang;MA Ying;XIE Yongchuan;SHEN Zhang;CHEN Wei;ZHU Guohui(School of Mechanical Engineering and Mechanics,Xiangtan University,Xiangtan,411105,China)

机构地区：[1]湘潭大学机械工程与力学学院,湖南湘潭411105

出　　处：《中南大学学报（自然科学版）》2024年第9期3543-3555,共13页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(52076184);湖南省自然科学基金资助项目(2023JJ10042,2021JJ30683,2022JJ40437)。

摘　　要：为研究汽油机冷启动过程产生的碳氢化合物在金属有机框架上的吸附和扩散行为特性,建立金属有机框架(MOFs)的计算模型,并验证模型的准确性。然后,对比分析C2H4和C6H6组分在沸石与MOFs上的吸附性能。最后,采用蒙特卡罗和分子动力学方法,分析C2H4、C6H6及等物质的量比混合组分在ZIF-20、ZIF-67、ZIF-318这3种MOFs结构的吸附性能和扩散性能。研究结果表明:与沸石材料相比,MOFs具有更优异的碳氢吸附效果。3种MOFs结构中,ZIF-20对C2H4和C6H6具有最大的吸附量,其吸附量分别为202.1和187.8个晶胞。在ZIF-20中C2H4的吸附位点主要集中在β-笼,C6H6的吸附位点主要集中在α-笼和双四元环。而在ZIF-67和ZIF-318中的吸附位点主要集中在十二元环。C2H4和C6H6分别在ZIF-318和ZIF-20中的扩散最强烈,且C2H4在3种MOFs上的扩散系数明显比C6H6的扩散系数大。To investigate the adsorption and diffusion behavior of hydrocarbons produced during cold start of gasoline engines on the metal-organic framework,the metal-organic frameworks(MOFs)calculation model was established and verified.Then,the adsorption performances of C2H4 and C6H6 on zeolites with MOFs were compared and analyzed.Finally,the adsorption and diffusion performance of C2H4,C6H6,and their equal molarratio mixture components on ZIF-20,ZIF-67,and ZIF-318 MOFs structures is analyzed using Monte Carlo and molecular dynamics methods.The results show that MOFs have better hydrocarbon adsorption effect than zeolite.Among the three MOFs structures,ZIF-20 has the largest adsorption capacity for C2H4 and C6H6,which is 202.1 and 187.8,respectively.The adsorption sites of C2H4 in ZIF-20 are mainly concentrated inβ-cage,and the adsorption sites of C6H6 are mainly concentrated inα-cage and biquaternary ring.In ZIF-67 and ZIF-318,the adsorption sites are mainly concentrated in the twelve-binary ring.The diffusion of C2H4 and C6H6 is the strongest in ZIF-318 and ZIF-20,respectively,and the diffusion coefficient of C2H4 is significantly greater than that of C6H6 on the three MOFs.

关 键 词：汽油机冷启动 碳氢吸附 MOFS 吸附 扩散 

分 类 号：TK411.5[动力工程及工程热物理—动力机械及工程]