A model for the effective thermal conductivity of moist porous building materials based on fractal theory

Wang, Yingying; Ma, Chao; Liu, Yanfeng; Wang, Dengjia; Liu, Jiaping

doi:10.1016/j.ijheatmasstransfer.2018.04.063

Cited by 55 publications

(15 citation statements)

References 27 publications

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“…The authors of papers [ 50 , 51 ] presented a fractal analysis of the effective thermal conductivity of unsaturated fractal porous media, which was conducted on the basis of a thermoelectrical analogy and the statistical similarity of the porous media. The authors proposed a physical model of the thermal conductivity of a three-phase medium: solid-liquid-gas.…”

Section: Resultsmentioning

confidence: 99%

Comparison of the Thermal Properties of Geopolymer and Modified Gypsum

et al. 2021

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The paper presents the results of research concerning the influence of micromaterials on the heat conductivity coefficient λ, specifically heat Cp and thermal diffusivity a of modified gypsum and geopolymer. Microspheres, hydroxyethyl methylcellulose (HEMC) polymer, and aerogel were used as the gypsum’s modifying materials. The study also investigated an alkali potassium-activated methakaolin-based geopolymer with the addition of aluminium dust. During the measurements of thermal parameters, the nonstationary method was chosen, and an Isomet device—which recorded the required physical quantities—was used. When compared to the reference sample, a decrease in the thermal conductivity and diffusivity of the hardened gypsum— and a simultaneous increase in specific heat—was observed with the addition of micromaterials. The geopolymer sample was characterized by the lowest value of thermal conductivity, equal to 0.1141 W/(m·K). It was over 62% lower than the reference sample containing only gypsum. The experimental values of the thermal conductivity of the gypsum samples with the addition of HEMC, aerogel and microspheres were, respectively, over 23%, 6%, and 8% lower than those of the unmodified gypsum samples. The lowest values of thermal conductivity were observed in the case of the gypsum samples modified with polymer; this resulted from the fact that the polymer caused the greatest change in the structure of the gypsum’s composite, which were expressed by the lowest density and highest porosity.

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Section: Resultsmentioning

confidence: 99%

Comparison of the Thermal Properties of Geopolymer and Modified Gypsum

et al. 2021

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“…Comprehensively comparing the fiber strength and its bonding force showed that the slope protection soil depends upon many factors including moisture fiber's content. As the studied soil is a porous medium, the fractal theory [18][19][20] can adopted for future research.…”

Section: Discussionmentioning

confidence: 99%

Model and performance analysis of coupled heat and moisture transfer of the roadbed slope

et al. 2022

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The soil samples of the roadbed slope of the Datong-Xi'an high-speed railway section are taken as the research object. The frost-heave property of the fiber soil of the roadbed slope under a single freeze-thaw cycle is studied, where the fiber's content is taken into account. The distributions of temperature and humidity fields inside the slope are numerically studied, and the coupling transfer of heat and moisture is revealed. The results are helpful for the optimal design of the roadbed slope

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“…Using the thermo-electrical analogy technique, the solution of heat conduction problem for fibrous medium can be obtained by decomposing the complex fibrous structure into a network consisting of a set of series/parallel structural elements (figure 1(c)) [24,31]. Thus, in the study, the Parallel-Series model [23,32], which is a combination of the series l^and the parallel l p models, was applied to predict the ETC of fabric sample at different moisture content state as follows…”

Section: Theoretical Methodology 21 Effective Thermal Conductivity mentioning

confidence: 99%

Investigating the effective thermal conductivity of moist fibrous fabric based on Parallel-Series model: a consideration of material’s swelling effect

Zhu

2020

Mater. Res. Express

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The aim of this work reported in the paper is to investigate the influence of moisture content on the effective thermal conductivity (ETC) of non-hygroscopic Polyethylene terephthalate (PET) and hygroscopic Viscose (VC) fabrics using Parallel-Series (P-S) thermal-electrical analogy method and TPS measurement. An equivalent porosity for hygroscopic fabric was first proposed to preserve the validity of the P-S model. The equivalent porosity is characterized by reasonably eliminating the absorbed moisture effects partly, which is embodied in enhancing heat conduction, endothermic reaction and swelling. Calculated values of the effective thermal conductivity of the two kinds of fabrics had been compared with experimental measurements. Results show that the P-S model incorporated with equivalent porosity is found to yield higher prediction accuracy than that of P-S model with parent porosity. The calibrated model can also provide a robust tool for predicting the global effective thermal conductivity of moist hygroscopic fibrous porous media. Nomenclature P-SParallel-Series ETC Effective thermal conductivity ΔP pressure difference r pore-throat radius || parallel ⊥ series T temperature

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A model for the effective thermal conductivity of moist porous building materials based on fractal theory

Cited by 55 publications

References 27 publications

Comparison of the Thermal Properties of Geopolymer and Modified Gypsum

Comparison of the Thermal Properties of Geopolymer and Modified Gypsum

Model and performance analysis of coupled heat and moisture transfer of the roadbed slope

Investigating the effective thermal conductivity of moist fibrous fabric based on Parallel-Series model: a consideration of material’s swelling effect

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