基于有效分子自由程的纳米孔隙气体传输模型  

A model for gas transport through nanopores based on effective molecular free path

作　　者：刘彦伟[1] 贾浩杰 左伟芹[1] 韩红凯 常平 苗健 魏建平[1] 徐鹏 LIU Yanwei;JIA Haojie;ZUO Weiqin;HAN Hongkai;CHANG Ping;MIAO Jian;WEI Jianping;XU Peng(School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo,Henan 454000,China;WA School of Mines:Minerals,Energy and Chemical Engineering,Curtin University,Kalgoorlie,WA 6430,Australia;School of Intelligent Engineering,Shandong Management University,Jinan,Shandong 250357,China;College of Science,China Jiliang University,Hangzhou,Zhejiang 310018,China)

机构地区：[1]河南理工大学安全科学与工程学院,河南焦作454000 [2]科廷大学西澳矿业学院,西澳大利亚卡尔古利6430 [3]山东管理学院智能工程学院,山东济南250357 [4]中国计量大学理学院,浙江杭州310018

出　　处：《中国矿业大学学报》2022年第1期90-99,共10页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(51774119,52174173);2019年度河南省高等学校重点科研项目计划基础专项(19zx003)。

摘　　要：煤体纳米孔隙内气体传输模型是低渗煤层瓦斯运移规律中尚未解决的关键科学问题之一,前人所建模型很少考虑微观边界限制对纳米孔隙通道内气体分子自由程的影响.论文根据气体动力学理论,修正了纳米尺度孔道内气体动力黏度及气体分子平均自由程,进而修正了Knudsen数;将修正的Knudsen数结合前人模型,建立了考虑微观边界限制的纳米孔隙气体传输模型,并推导出了等效视渗透率模型.采用场发射扫描电子显微镜和MATLAB最大稳定极值区域算法,量化表征了阳极氧化铝薄膜纳米孔的孔隙结构;使用PMI微渗透率测试仪,开展了不同稀薄程度气体的薄膜穿透实验,验证了考虑微观边界限制的纳米孔隙气体传输模型.结果表明:受微观边界限制影响,纳米孔隙内气体分子平均自由程和有效Knudsen数均会减小;与传统模型相比,新建考虑微观边界限制的纳米孔隙气体传输模型与实验结果更为相近,且适用于描述多尺度孔隙内气体流动规律.The model for gas transport processes occurring in nanopore channels is one of the unsolved key scientific issues in the gas migration law of low-permeability coal seam.Previous models rarely considered the influence of microscopic boundary constraints on the mean-free path of gas molecules in nanopore channels.Based on the gas dynamics theory,the gas dynamic viscosity,the mean-free path and the Knudsen number in nano-scale channels were modified.Combining the effective Knudsen number with previous models,a gas transport model with micro-boundary constraints was constructed,and the equivalent apparent permeability model was deduced.The pore structure of nanopores in anodized aluminum membrane was quantitatively characterized by field emission scanning electron microscopy(FESEM)and maximally stable extremal regions(MSER)algorithm of MATLAB.The penetration experiments of anodized aluminum membrane with different rarefied gases were carried out by PMI micro-flow permeability tester,and the nanopores gas transport model considering micro-boundary limitation was validated.The results show that the mean-free path of gas molecule and effective Knudsen number in the nanopores become smaller due to the micro-boundary restriction.Compared with the traditional model,the new nanopores gas transport model considering the micro-boundary limitation is more consistent with the experimental results and is suitable to describe gas flow law in multi-scale pores.

关 键 词：微观边界限制 气体分子平均自由程 视渗透率模型 最大稳定极值区域算法 阳极氧化铝薄膜实验 

分 类 号：X936[环境科学与工程—安全科学]