An effective thermal conductivity model for fractal porous media with rough surfaces

Qin, Xuan; Zhou, Yingfang; Sasmito, Agus P.

doi:10.26804/ager.2019.02.04

Cited by 37 publications

(7 citation statements)

References 40 publications

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“…Quantitative evaluation of the effective thermal conductivity of porous media has received wide attention in scientific investigations and engineering. The influence of geometrical factors, porosity and relative surface roughness on the effective thermal conductivity in porous media were discussed and analyzed in Qin et al (2019).…”

Section: Introductionmentioning

confidence: 99%

Darcy–Brinkman–Forchheimer Model for Film Boiling in Porous Media

et al. 2020

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The paper presents results of the modelling of heat transfer at film boiling of a liquid in a porous medium on a vertical heated wall bordering with the porous medium. Such processes are observed at cooling of high-temperature surfaces of heat pipes, microstructural radiators etc. Heating conditions at the wall were the constant wall temperature or heat flux. The outer boundary of the vapor film was in contact with moving or stationary liquid inside the porous medium. An analytical solution was obtained for the problem of fluid flow and heat transfer using the porous medium model in the Darcy–Brinkman and Darcy–Brinkman–Forchheimer approximation. It was shown that heat transfer at film boiling in a porous medium was less intensive than in the absence of a porous medium (free fluid flow) and further decreased with the decreasing permeability of the porous medium. Significant differences were observed in frames of both models: 20% for small Darcy numbers at Da < 2 for the Darcy–Brinkman model, and 80% for the Darcy–Brinkman–Forchheimer model. In the Darcy–Brinkman model, depending on the interaction conditions at the vapor–liquid interface (no mechanical interaction or stationary fluid), a sharp decrease in heat transfer was observed for the Darcy numbers lower than five. The analytical predictions of heat transfer coefficients qualitatively agreed with the data of Cheng and Verma (Int J Heat Mass Transf 24:1151–1160, 1981) though demonstrated lower values of heat transfer coefficients for the conditions of the constant wall temperature and constant wall heat flux.

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Section: Introductionmentioning

confidence: 99%

Darcy–Brinkman–Forchheimer Model for Film Boiling in Porous Media

et al. 2020

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“…In recent years, many researchers began to investigate the effects of rough morphology and wall-fluid interaction on thermal characteristics (Cao et al, 2006;Chakraborty et al, 2019;Qin et al, 2019;Motlagh and Kalteh, 2020). Chen and Zhang (2014) conducted a molecular dynamics simulation of ETC in rough nanochannels to investigate how surface topography, which characterized by the fractal Cantor structure, affects the thermal conductance at liquid-solid interfaces.…”

Section: Introductionmentioning

confidence: 99%

A Fractal Model for Effective Thermal Conductivity in Complex Geothermal Media

Zeng

Zhang

et al. 2022

Front. Earth Sci.

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Thermal conductivity is an important macroscopic thermo-physical parameter due to its significant effects on the temperature field distribution and heat flow magnitude in the material at heat conduction equilibrium. However, because of the extremely complex pore structure and disordered pore distribution, a well-accepted relationship between effective thermal conductivity (ETC) and geometric structural parameters is still lack. In this study, a novel fractal model with variation pore diameter is established systematically based on the assumption that the rough elements of wall surface, pore size distribution and capillary tortuosity follow the fractal scaling law. Thermal-electrical analogy is introduced to predict the ETC of unsaturated geothermal media. The proposed model explicitly relates the ETC to the microstructural parameters (relative roughness, porosity, fractal dimensions and radius fluctuation amplitude) and fluid properties. The proposed model is validated by comparing with existing experimental data. A parametric analysis is performed for presenting the effects of the structural parameters and fluid properties on the ETC. The results show that pore structure has significant effect on ETC of unsaturated porous media. ETC gradually decreases with the increment of porosity, relative roughness, and fractal dimensions. The present study improves the accuracy in predicting ETC and sheds light on the heat transfer mechanisms of geothermal media.

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“…Civan et al propose an improved shale gas transport model that can be used to determine the diffusion coefficient and permeability of shales [18]. Additionally, many published models have investigated the seepage properties of pore rocks which do not satisfy the Darcy's law of permeability [19,20]. However, the throat connecting the rock pores is irregular and unevenly distributed.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Analysis of the Topological Structure of Rock Pore Network

Liu

Luo

et al. 2021

Geofluids

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As the most significant nonlinear reservoir, the rocks have complex structural characteristic. The pore structure of the rock is varied in shape and complex in connectivity. However, the prevailing methods for characterising the microstructure of rocks, such as the coordination number method and fractal theory, are still difficult to quantify the structural properties. In this study, based on the CT-scan method and a new complex network theory, the topological characteristics of rocks such as seepage path selection, degree of pore aggregation, pore importance, and pore module structure are analysed. The results show that the scale-free network model is more reliable in characterising the rock pore network than previously published structural models, and a small number of pores are the “key” to the seepage process. Besides, we proposed a new method to quantify the importance of rock pores and present the distribution characteristics and connectivity laws of the rock-pore network. This provides a new method to study the seepage process of the nonlinear reservoirs.

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An effective thermal conductivity model for fractal porous media with rough surfaces

Cited by 37 publications

References 40 publications

Darcy–Brinkman–Forchheimer Model for Film Boiling in Porous Media

Darcy–Brinkman–Forchheimer Model for Film Boiling in Porous Media

A Fractal Model for Effective Thermal Conductivity in Complex Geothermal Media

Quantitative Analysis of the Topological Structure of Rock Pore Network

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