NUMERICAL PREDICTIONS OF THE EFFECTIVE THERMAL CONDUCTIVITY FOR MULTIPHASE POROUS BUILDING MATERIALS

2015 ◽  
Author(s):  
Mazhar Hussain ◽  
Ya-Ling He ◽  
Wen-Quan Tao
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Building Materials ◽  
Porous Building Materials ◽  
Numerical Predictions

Effective thermal conductivity of porous building materials - analysis and verification

Bauphysik ◽  
2008 ◽  
Vol 30 (6) ◽  
pp. 431-433 ◽  
Author(s):  
Jerzy Wyrwał ◽  
Andrzej Marynowicz ◽  
Jadwiga Świrska
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Building Materials ◽  
Materials Analysis ◽  
Porous Building Materials

scholarly journals A 3D model to predict the influence of nanoscale pores or reduced gas pressures on the effective thermal conductivity of cellular porous building materials

2019 ◽  
Vol 43 (4) ◽  
pp. 277-300 ◽  
Author(s):  
Wouter Van De Walle ◽  
Hans Janssen
Keyword(s):  
Thermal Conductivity ◽  
Porous Materials ◽  
Effective Thermal Conductivity ◽  
Building Materials ◽  
Full Range ◽  
Advanced Materials ◽  
Future Application ◽  
High Porosity ◽  
Pore Sizes ◽  
Gas Pressures

Cellular porous materials are frequently applied in the construction industry, both for structural and insulation purposes. The progressively stringent energy regulations mandate the development of better performing insulation materials. Recently, novel porous materials with nanopores or reduced gas pressures have been shown to possess even lower thermal conductivities because of the Knudsen effect inside their pores. Further understanding of the relation between the pore structure and the effective thermal conductivity is needed to quantify the potential improvement and design new optimized materials. This article presents the extension of a 3D numerical framework simulating the heat transfer at the pore scale. A novel methodology to model the reduced gas-phase conductivity in nanopores or at low gas pressures is presented, accounting for the 3D pore geometry while remaining computationally efficient. Validation with experimental and numerical results from the literature indicates the accuracy of the methodology over the full range of pore sizes and gas pressures. Combined with an analytical model to account for thermal radiation, the framework is applied to predict the thermal conductivity of a nanocellular poly(methyl methacrylate) foam experimentally characterized in the literature. The simulation results show excellent agreement with less than 5% difference with the experimental results, validating the model’s performance. Furthermore, results also indicate the potential improvements when decreasing the pore size from the micrometre to the nanometre range, mounting up to 40% reduction for such high-porosity low-matrix-conductivity materials. Future application of the model could assist the design of advanced materials, properly accounting for the effect of reduced pore sizes and gas pressures.

Comprehensive correction of thermal conductivity of moist porous building materials with static moisture distribution and moisture transfer

Energy ◽  
2019 ◽  
Vol 176 ◽  
pp. 103-118 ◽  
Author(s):  
Yingying Wang ◽  
Zejiao Zhao ◽  
Yanfeng Liu ◽  
Dengjia Wang ◽  
Chao Ma ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Building Materials ◽  
Moisture Transfer ◽  
Moisture Distribution ◽  
Porous Building Materials
Sign in / Sign up

Export Citation Format

Share Document