CAJ | 학술논문

为研究气凝胶纳米颗粒的导热特性，提出了一种基于随机统计原理的构造气凝胶多孔介质介观尺度三维物理模型的方法。模型中颗粒空间分布、粒径分布及孔隙率可以根据实际气凝胶微尺度结构数据调整。基于所构造的物理模型，采用D3Q15LBM进行了数值模拟。分析了颗粒尺寸、孔隙率等因素对气凝胶导热性能的影响规律，即在既定孔隙率下，热导率随粒径增大而减小；既定粒径下，随孔隙率的递增热导率先下降后上升；颗粒尺寸不均匀性对热导率的影响甚大。模拟与实验结果相吻合。研究工作对优化气凝胶导热性能，提高其有效热导率的预测精度具有参考价值。
위연구기응효납미과립적도열특성，제출료일충기우수궤통계원리적구조기응효다공개질개관척도삼유물리모형적방법。모형중과립공간분포、립경분포급공극솔가이근거실제기응효미척도결구수거조정。기우소구조적물리모형，채용D3Q15LBM진행료수치모의。분석료과립척촌、공극솔등인소대기응효도열성능적영향규률，즉재기정공극솔하，열도솔수립경증대이감소；기정립경하，수공극솔적체증열도솔선하강후상승；과립척촌불균균성대열도솔적영향심대。모의여실험결과상문합。연구공작대우화기응효도열성능，제고기유효열도솔적예측정도구유삼고개치。
To study the thermal property of silica aerogel, a method is proposed for constructing three-dimensional mesoscopic physical model of nanoparticle porous materials, based on the random statistical theory. The spatial distribution of particles, particle size and porosity can be adjusted according to actual microscopic information of the porous material. D3Q15LBM model is employed to perform numerical simulation and analysis in mesoscopic scale. And the influence of particle diameter, porosity and other factors on thermal conductivity of porous media is analyzed. That is, the thermal conductivity will decrease with the increase of particle size for constant porosity; the thermal conductivity falls and then rises as the porosity increases for constant particle size; the uniformity of particle size plays an important role on the thermal property. The simulation results are nearly the same with the experimental ones. The research will be an excellent reference for optimization of thermal performance and prediction of effective thermal conductivity for aerogels.