首页|Theoretical study on the effective thermal conductivity of silica aerogels based on a cross-aligned and cubic pore model

Theoretical study on the effective thermal conductivity of silica aerogels based on a cross-aligned and cubic pore model

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Aerogel nanoporous materials possess high porosity,high specific surface area,and extremely low density due to their unique nanoscale network structure.Moreover,their effective thermal conductivity is very low,making them a new type of lightweight and highly efficient nanoscale super-insulating material.However,prediction of their effective thermal conductivity is challenging due to their uneven pore size distribution.To investigate the internal heat transfer mechanism of aerogel nanoporous materials,this study constructed a cross-aligned and cubic pore model(CACPM)based on the actual pore arrangement of SiO2 aerogel.Based on the established CACPM,the effective thermal conductivity expression for the aerogel was derived by simultaneously considering gas-phase heat conduction,solid-phase heat conduction,and radiative heat transfer.The derived expression was then compared with available experimental data and the Wei structure model.The results indicate that,according to the model established in this study for the derived thermal conductivity formula of silica aerogel,for powdery silica aerogel under the conditions of T=298 K,a2=0.85,D1=90 μm,ρ=128 kg/m3,within the pressure range of 0-105 Pa,the average deviation between the calculated values and experimental values is 10.51％.In the pressure range of 103-104 Pa,the deviation between calculated values and experimental values is within 4％.Under these conditions,the model has certain reference value in engineering verification.This study also makes a certain contribution to the research of aerogel thermal conductivity heat transfer models and calculation formulae.

silica aerogeleffective thermal conductivitytwo pore-size structure modelporous medium heat transfer

郑坤灿、李震东、曹豫通、刘犇、胡君磊

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School of Energy and Environment,Inner Mongolia University of Science and Technology,Baotou 014010,China

Inner Mongolia Key Laboratory of Efficient and Clean Combustion,Baotou 014010,China

国家自然科学基金国家自然科学基金Inner Mongolia Autonomous Region Postgraduate Research Innovation Project of ChinaResearch Program of Science and Technology at Universities of Inner Mongolia Autonomous Region of ChinaResearch Program of Science and Technology at Universities of Inner Mongolia Autonomous Region of China

5176404652160013S20231165Z2023RCTD0162024RCTD008

2024

10.1088/1674-1056/ad47ac

中国物理B(英文版)
中国物理学会和中国科学院物理研究所

中国物理B(英文版)

CSTPCDEI
影响因子：0.995
ISSN：1674-1056
年,卷(期)：2024.33(6)
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