Pore Network Simulation and Experimental Investigation on Water-Heat Transport Process of Soil Porous Media

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Yuejin Yuan ◽  
Libin Tan ◽  
Zhe Zhao ◽  
Yingying Xu ◽  
Miaomiao Bai ◽  
...  
Keyword(s):  
Porous Media ◽  
Heat Transport ◽  
Sandy Soil ◽  
Transport Process ◽  
Network Simulation ◽  
Pore Network ◽  
Two Dimensional ◽  
Simulation Results ◽  
Heat Transport Process ◽  
Good Agreement

The research on water-heat transport of soil porous media has important theoretical and practical significance for the problem of agricultural production and environmental governance. In this work, the water-heat transport characteristics of sandy soil porous media are analyzed. The two-dimensional continuum physical model is constructed by continuum method, and the two-dimensional pore network physical model is constructed directly at pore scale by taking into account the complicated pore and skeleton structures of soil. Mathematical models of water-heat transport process of sandy soil are constructed based on heat-mass transfer mechanism. Mathematical models of the continuum method and pore network method are solved by ANSYS and self-designed solving algorithm, respectively. The numerical simulation results of soil temperature distributions and moisture distributions are in good agreement with the experimental results. The pore network simulation results are in good agreement with the measured data and are superior to the existing continuous scale method. The pore network simulation results can directly present the characteristics of the preferential flow and wetting front during the water-heat transport process of soil.

Laser heating of semiconductors—effect of carrier diffusion in nonlinear dynamic heat transport process

1981 ◽  
Vol 52 (8) ◽  
pp. 4995-5006 ◽  
Author(s):  
Dae M. Kim ◽  
D. L. Kwong ◽  
Rajiv R. Shah ◽  
D. Lloyd Crosthwait
Keyword(s):  
Heat Transport ◽  
Nonlinear Dynamic ◽  
Laser Heating ◽  
Transport Process ◽  
Carrier Diffusion ◽  
Heat Transport Process

Effects of Materials on Formation of Double-Layered Liners Shaped Charges

2009 ◽  
Vol 79-82 ◽  
pp. 1277-1280
Author(s):  
Yu Zheng ◽  
Xiao Ming Wang ◽  
Wen Bin Li ◽  
Wen Jin Yao
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Numerical Simulations ◽  
Double Layer ◽  
Two Dimensional ◽  
Materials Properties ◽  
X Ray ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Good Agreement

In order to study the effects of liner materials on the formation of Shaped Charges with Double Layer Liners (SCDLL) into tandem Explosively Formed Projectile (EFP), the formation mechanism of DLSCL was studied. Utilizing two-dimensional finite element dynamic code AUTODYN, the numerical simulations on the mechanical phenomenon of SCDLL forming into tandem EFP were carried out. X-ray pictures were obtained after Experiments on SCDLL. Comparisons between experimental results and numerical simulation results have good agreement. It can be concluded from the results that the materials properties and configurations of both liners are crucial to the formation of tandem EFP.

Two-Dimensional Numerical Analysis of Non-Darcy Flow Using the Lattice Boltzmann Method: Pore-Scale Heterogeneous Effects

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Yuto Takeuchi ◽  
Junichiro Takeuchi ◽  
Tomoki Izumi ◽  
Masayuki Fujihara
Keyword(s):  
Porous Media ◽  
Lattice Boltzmann ◽  
Darcy Flow ◽  
Two Dimensional ◽  
Pore Scale ◽  
Scale Heterogeneity ◽  
Simulation Results ◽  
Channeling Effect ◽  
Boltzmann Method ◽  
Participation Number

Abstract This study simulates pore-scale two-dimensional flows through porous media composed of circular grains with varied pore-scale heterogeneity to analyze non-Darcy flow effects on different types of porous media using the lattice Boltzmann method. The magnitude of non-Darcy coefficients and the critical Reynolds number of non-Darcy flow were computed from the simulation results using the Forchheimer equation. Although the simulated porous materials have similar porosity and representative grain diameters, larger non-Darcy coefficients and an earlier onset of non-Darcy flow were observed for more heterogeneous porous media. The simulation results were compared with existing correlations to predict non-Darcy coefficients, and the large sensitivity of non-Darcy coefficients to pore-scale heterogeneity was identified. The pore-scale heterogeneity and resulting flow fields were evaluated using the participation number. From the computed participation numbers and visualized flow fields, a significant channeling effect for heterogeneous media in the Darcy flow regime was confirmed compared with that for homogeneous media. However, when non-Darcy flow occurs, this channeling effect was alleviated. This study characterizes non-Darcy effect with alleviation of the channeling effect quantified with an increase in participation number. Our findings indicate a strong sensitivity of magnitude and onset of non-Darcy effect to pore-scale heterogeneity and imply the possibility of evaluating non-Darcy effect through numerical analysis of the channeling effect.

Pore-Network Simulation of Unstable Miscible Displacements in Porous Media

2016 ◽  
Vol 113 (3) ◽  
pp. 511-529 ◽  
Author(s):  
Mahnaz Hekmatzadeh ◽  
Mitra Dadvar ◽  
Muhammad Sahimi
Keyword(s):  
Porous Media ◽  
Network Simulation ◽  
Pore Network ◽  
Miscible Displacements

SIMULATION STUDY ON BREAKDOWN BEHAVIOR OF FIELD-PLATE SiC MESFETs

2004 ◽  
Vol 14 (03) ◽  
pp. 884-889 ◽  
Author(s):  
HO-YOUNG CHA ◽  
Y. C. CHOI ◽  
LESTER F. EASTMAN ◽  
MICHAEL G. SPENCER
Keyword(s):  
Breakdown Voltage ◽  
Simulation Study ◽  
Two Dimensional ◽  
Plate Structures ◽  
Field Plate ◽  
Simulation Results ◽  
Good Agreement

The effects of field-plate structures on SiC MESFETs were investigated using two-dimensional simulations. The simulation results without a field-plate were in good agreement with the characteristics of fabricated SiC MESFETs. The breakdown voltage was increased by 80 % when the optimum field-plate was applied to the device with a 0.5 μm long gate and a 1 μm spacing between gate and drain; a breakdown voltage of 240 – 250 V was obtained from a 0.35 μm field-plate, while 140 V was obtained without a field-plate.

Thermal Simulations for Cooling Rate Mapping in Electron Beam Additive Manufacturing

2015 ◽  
Author(s):  
Bo Cheng ◽  
Y. Kevin Chou
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Heat Source ◽  
Cooling Rate ◽  
Heat Transport ◽  
Process Parameters ◽  
Transport Process ◽  
Thermal Model ◽  
Heat Transport Process

The powder-bed electron beam additive manufacturing (EBAM) process is a relatively new AM technology that utilizes a high-energy heat source to fabricate metallic parts in a layer by layer fashion by melting metal powder in selected regions. EBAM can be able to produce full density part and complicated components such as near-net-shape parts for medical implants and internal channels. However, the large variation in mechanical properties of AM build parts is an important issue that impedes the mass production ability of AM technology. It is known that the cooling rate in the melt pool directly related to the build part microstructure, which greatly influences the mechanical properties such as strength and hardness. And the cooling rate is correlated to the basic heat transport process physics in EBAM, which includes a moving heat source and rapid self-cooling process. Therefore, a better understanding of the thermal process of the EBAM process is necessary. In this study, a 3D thermal model, using a finite element method (FEM), was utilized for EBAM heat transport process simulations. The process temperature prediction offers information of the cooling rate during the heating-cooling cycle. The thermal model is applied to evaluate, for the case of Ti-6Al-4V in EBAM, the process parameter effects, such as the beam speed and power, on the temperature profile along the melt scan and the corresponding cooling rate characteristics. The relationship between cooling rates and process parameters is systematically investigated, through multiple simulations, by incorporating different combinations of process parameters into the thermal model. The beam scanning speed vs. beam power curves of constant cooling rates can be obtained from 3D surface plots (cooling rate vs. different process parameters), which may facilitate the process parameters selections and achieve consistent build part quality through controlling the cooling rate.

Model Testing and CFD Analysis of 2D Profiles Towards Offshore Applications

2013 ◽  
Author(s):  
Lucas do Vale Machado ◽  
Antonio Carlos Fernandes ◽  
Gustavo César Rachid Bodstein
Keyword(s):  
Experimental Data ◽  
Experimental Measurements ◽  
Cfd Analysis ◽  
Two Dimensional ◽  
Reference Simulation ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Naca 0015 ◽  
Good Agreement

In this paper we present numerical and experimental work motivated by the study of a rudder profile with significant levels of lift that provides better performance for the maneuvering and stabilization of a ship. This is the so-called Schilling profile. The analysis of the two-dimensional subsonic steady flow over four profiles was carried out using computational fluid dynamics (CFD) tools with a κ-ω SST turbulence model. We consider three Schilling profiles with different thicknesses and the classical NACA 0015 profile, taken as a reference. Simulation results were compared to our experimental measurements at various angles of attack and two orders of magnitude of the Reynolds number, 5.45 × 104 and 1.09 × 105. The numerical results show general good agreement with experimental data and highlight the distinct behavior of Schilling profile.

Numerical and Experimental Fractal Pore Network Study on Drying of Porous Media: Model Building

2012 ◽  
Vol 557-559 ◽  
pp. 2159-2162
Author(s):  
Yue Jin Yuan ◽  
Yue Ding Yuan ◽  
Ying Ying Xu ◽  
Ji Xian Dong ◽  
Xiang Dong Liu
Keyword(s):  
Porous Media ◽  
Network Model ◽  
Transport Process ◽  
Model Building ◽  
Pore Network ◽  
Pore Network Model ◽  
Drying Process ◽  
Porous Media Model ◽  
Diffusion Temperature ◽  
Microstructure Characteristic

In view of the fact that the two-dimensional square pore network model screened many microstructure features and transfer characteristics inside porous media, a fractal pore network model for unsteady drying process of natural porous body was developed on the base of fractal geometry theory and transport process principle, which took various factors into consideration, such as the liquid-phase flow, vapor-phase diffusion, temperature gradient, and pore microstructure characteristic.

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