XU Guowen, LI Kun, JIANG Yifan, HUANG Mingjun, FANG Dongxu, CAI Shanshan. Mesoscopic study on effective thermal conductivity of dry soil under three types of random fractal structures[J]. CIESC Journal, 2019, 70(7): 2496-2502
XU Guowen, LI Kun, JIANG Yifan, HUANG Mingjun, FANG Dongxu, CAI Shanshan. Mesoscopic study on effective thermal conductivity of dry soil under three types of random fractal structures[J]. CIESC Journal, 2019, 70(7): 2496-2502DOI: 10.11949/j.issn.0438-1157.20181504.
Mesoscopic study on effective thermal conductivity of dry soil under three types of random fractal structures
The heat transfer capacity of the ground heat exchanger is the key to designing the ground source heat pump system
and the effective thermal conductivity of the environmental soil is an important parameter affecting the underground heat transfer. To further investigate the impacts of mesoscopic structural parameters on the effective thermal conductivity of soil
this paper proposes three random fractal structures and applys lattice Boltzmann method to simulate the heat transfer procedure in the soil-like porous materials. By comparing and analyzing the simulation results with the experimental findings which are derived from thermal probe tests
it is found that porosity is still the dominant factor that affects the effective thermal conductivity of dry soil
while the impacts of fractal dimension and size ratio are minor. The randomness of phase distribution in the dry soil does have considerable effect on the variations of effective thermal conductivity. A slight change of the particle distribution can lead to a difference up to 24.5%.
关键词
Keywords
references
Dong Y , Mccartney J S , Lu N . Critical review of thermal conductivity models for unsaturated soils [J ] . Geotechnical and Geological Engineering , 2015 , 33 ( 2 ): 207 - 221 .
Alrtimi A , Rouainia M , Haigh S . Thermal conductivity of a sandy soil [J ] . Applied Thermal Engineering , 2016 , 106 : 551 - 560 .
Zhang N , Wang Z Y . Review of soil thermal conductivity and predictive models [J ] . International Journal of Thermal Sciences , 2017 , 117 : 172 - 183 .
Turcotte D L . Fractals and fragmentation [J ] . Journal of Geophysical Research , 1986 , 91 (B 2 ): 1921 - 1926 .
Yang P L , Luo Y P , Shi Y C . Fractal characteristics of soil characterized by weight distribution of particle sizes [J ] . Chinese Science Bulletin , 1993 , 38 ( 20 ): 1896 - 1899 .
Kou J L , Wu F M , Lu H J , et al . The effective thermal conductivity of porous media based on statistical self-similarity [J ] . Physics Letters A , 2009 , 374 ( 1 ): 62 - 65 .
Cai S S , Cui T F , Zheng B R , et al . A fractal approach to calculate the thermal conductivity of moist soil [C ] // Proceedings of the IGSHPA Technical/Research Conference and Expo 2017. Denver: IGSHPA , 2017 : 420 - 429 .
Lehmann P , Stähli M , Papritz A , et al . A fractal approach to model soil structure and to calculate thermal conductivity of soils [J ] . Transport in Porous Media , 2003 , 52 ( 3 ): 313 - 332 .
Thompson A H , Katz A J , Krohn C E . The microgeometry and transport properties of sedimentary rock [J ] . Advances in Physics , 1987 , 36 ( 5 ): 625 - 694 .
Qin X , Cai J C , Xu P , et al . A fractal model of effective thermal conductivity for porous media with various liquid saturation [J ] . International Journal of Heat and Mass Transfer , 2019 , 128 : 1149 - 1156 .
Wang Y Y , Ma C , Liu Y F , et al . A model for the effective thermal conductivity of moist porous building materials based on fractal theory [J ] . International Journal of Heat and Mass Transfer , 2018 , 125 : 387 - 399 .
Zhang D H , Jin F , Shi M H , et al . Heat conduction in fractal porous media [J ] . Journal of Applied Sciences , 2003 , 21 ( 3 ): 253 - 257 .
Jin H Q , Yao X L , Fan L W , et al . Experimental determination and fractal modeling of the effective thermal conductivity of autoclaved aerated concrete: effects of moisture content [J ] . International Journal of Heat and Mass Transfer , 2016 , 92 : 589 - 602 .
Ju Y , Zheng J T , Epstein M , et al . 3D numerical reconstruction of well-connected porous structure of rock using fractal algorithms [J ] . Computer Methods in Applied Mechanics and Engineering , 2014 , 279 : 212 - 226 .
Yu B M , Zou M Q , Feng Y J . Permeability of fractal porous media by Monte Carlo simulations [J ] . International Journal of Heat and Mass Transfer , 2005 , 48 ( 13 ): 2787 - 2794 .
Maier R S , Bernard R S . Lattice-Boltzmann accuracy in pore-scale flow simulation [J ] . Journal of Computational Physics , 2010 , 229 ( 2 ): 233 - 255 .
Zhang X X , Crawford J W , Young I M . A lattice Boltzmann model for simulating water flow at pore scale in unsaturated soils [J ] . Journal of Hydrology , 2016 , 538 : 152 - 160 .
Fan H , Zheng H . MRT-LBM-based numerical simulation of seepage flow through fractal fracture networks [J ] . Science China Technological Sciences , 2013 , 56 ( 12 ): 3115 - 3122 .
Wang M R , Wang J K , Pan N , et al . Three-dimensional effect on the effective thermal conductivity of porous media [J ] . Journal of Physics D: Applied Physics , 2007 , 40 ( 1 ): 260 - 265 .
Wang M R , Pan N . Modeling and prediction of the effective thermal conductivity of random open-cell porous foams [J ] . International Journal of Heat and Mass Transfer , 2008 , 51 ( 5 / 6 ): 1325 - 1331 .
Fang W Z , Chen L , Gou J J , et al . Predictions of effective thermal conductivities for three-dimensional four-directional braided composites using the lattice Boltzmann method [J ] . International Journal of Heat and Mass Transfer , 2016 , 92 : 120 - 130 .
Cui Z D , Jia Y J . Analysis of electron microscope images of soil pore structure for the study of land subsidence in centrifuge model tests of high-rise building groups [J ] . Engineering Geology , 2013 , 164 : 107 - 116 .
Cai S S , Zhang B X , Cui T F , et al . Mesoscopic study of the effective thermal conductivity of dry and moist soil [J ] . International Journal of Refrigeration , 2019 , 98 : 171 - 181 .
Yu B M . Fractal character for tortuous streamtubes in porous media [J ] . Chinese Physics Letters , 2005 , 22 ( 1 ): 158 - 160 .
Chen X , Han P . A note on the solution of conjugate heat transfer problems using SIMPLE-like algorithms [J ] . International Journal of Heat and Fluid Flow , 2000 , 21 ( 4 ): 463 - 467 .
Wang M R , Wang J K , Pan N , et al . Mesoscopic predictions of the effective thermal conductivity for microscale random porous media [J ] . Physical Review E , 2007 , 75 ( 3 ): 036702 .
Ginzburg I , Verhaeghe F , D'Humières D . Two-relaxation-time lattice Boltzmann scheme: about parametrization, velocity, pressure and mixed boundary conditions [J ] . Communications in Computational Physics , 2008 , 3 ( 2 ): 427 - 478 .
D'Orazio A , Corcione M , Celata G P . Application to natural convection enclosed flows of a lattice Boltzmann BGK model coupled with a general purpose thermal boundary condition [J ] . International Journal of Thermal Sciences , 2004 , 43 ( 6 ): 575 - 586 .
Zou Q S , He X Y . On pressure and velocity boundary conditions for the lattice Boltzmann BGK model [J ] . Physics of Fluids , 1997 , 9 ( 6 ): 1591 - 1598 .
Cui T F . Full-scale heat transfer analysis of ground heat exchangers with the effect of groundwater flow [D ] . Wuhan : Huazhong University of Science and Technology , 2018 .
Mandelbrot B B . The Fractal Geometry of Nature [M ] . New York : W. H . Freeman and Co ., 1983 .