Pub Date : 2024-09-01DOI: 10.1615/jpormedia.2024052733
Na Zhang, Yu Song, Yuxin Ren, Piaopiao Zhang, Ziyun Zhang, Shuaidong Wang
ABSTRACT: A significant aspect influencing engineering stability in deep engineering is temperature. In order to explore the influence of high temperature on sandstone, This study used experimental samples of sandstone from Shaanxi, China. Sandstone samples were subjected to varying temperature gradients (25℃, 100℃, 300℃, 500℃ and 700℃) for Uniaxial Compressive Strength (UCS), Acoustic Emission (AE) monitoring, and Nuclear Magnetic Resonance (NMR) experiments. The resulting mechanical parameters and pore diameter distributions of the sandstone under various temperatures were compared and analyzed. The results showed that: Peak strain and peak stress of sandstone samples both greatly rise and decrease with increasing heating temperature. The degree of elastic modulus and peak stress degradation is also more pronounced at higher temperatures. The brittle-ductile transition occurs at about occurs between 500°C~700°C. At temperatures between 25°C and 500°C, the peak AE energy occurs near the peak strength of the sandstone. The ringing counts of the sandstone specimens reached a maximum after the peak stress when the temperature was 700°C, and the peak AE energy gradually decreased at higher heating temperatures. The T2 spectrum curve and pore size curve of the sandstone increased and gradually shifted to the right with the increase of the treatment temperature, and the area of the T2 spectrum and porosity also gradually increased. There is a negative correlation between porosity and total area of T2 spectrum and peak stress and elastic modulus of sandstone under high temperature. The micropores showed a monotonically decreasing trend with increasing temperature
{"title":"Multi‑scale Experimental Investigations on the Deterioration Mechanism of Sandstone after high-temperature treatment","authors":"Na Zhang, Yu Song, Yuxin Ren, Piaopiao Zhang, Ziyun Zhang, Shuaidong Wang","doi":"10.1615/jpormedia.2024052733","DOIUrl":"https://doi.org/10.1615/jpormedia.2024052733","url":null,"abstract":"ABSTRACT: A significant aspect influencing engineering stability in deep engineering is temperature. In order to explore the influence of high temperature on sandstone, This study used experimental samples of sandstone from Shaanxi, China. Sandstone samples were subjected to varying temperature gradients (25℃, 100℃, 300℃, 500℃ and 700℃) for Uniaxial Compressive Strength (UCS), Acoustic Emission (AE) monitoring, and Nuclear Magnetic Resonance (NMR) experiments. The resulting mechanical parameters and pore diameter distributions of the sandstone under various temperatures were compared and analyzed. The results showed that: Peak strain and peak stress of sandstone samples both greatly rise and decrease with increasing heating temperature. The degree of elastic modulus and peak stress degradation is also more pronounced at higher temperatures. The brittle-ductile transition occurs at about occurs between 500°C~700°C. At temperatures between 25°C and 500°C, the peak AE energy occurs near the peak strength of the sandstone. The ringing counts of the sandstone specimens reached a maximum after the peak stress when the temperature was 700°C, and the peak AE energy gradually decreased at higher heating temperatures. The T2 spectrum curve and pore size curve of the sandstone increased and gradually shifted to the right with the increase of the treatment temperature, and the area of the T2 spectrum and porosity also gradually increased. There is a negative correlation between porosity and total area of T2 spectrum and peak stress and elastic modulus of sandstone under high temperature. The micropores showed a monotonically decreasing trend with increasing temperature","PeriodicalId":50082,"journal":{"name":"Journal of Porous Media","volume":"60 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1615/jpormedia.2024053135
Esmari Maré, Sonia Fidder
In open-cell foams solid lumps are often present at the intersection of struts, known as the nodes. In this study models available in the literature that represent foams with solid accumulation at the nodes are investigated and used to obtain predictive equations for the permeability (for both the Darcy and Forchheimer flow regimes) and specific surface area for given porosity and average pore diameter values. The majority of the predictive equations proposed for the specific surface area based on these models are novel contributions. Furthermore, a method is proposed for incorporating solid lumps at the nodes into the existing foam (or three-strut) rectangular Representative Unit Cell (RUC) model. The models obtained from the literature along with the node adjusted RUC model are compared to one another and to relevant experimental data from the literature for foams that have accumulation of solid matter present at the nodes. The node adjusted RUC model provides physically meaningful and satisfactory changes to the specific surface area and permeability predictions of the existing foam RUC model.
{"title":"Geometric models for incorporating solid accumulation at the nodes of open-cell foams","authors":"Esmari Maré, Sonia Fidder","doi":"10.1615/jpormedia.2024053135","DOIUrl":"https://doi.org/10.1615/jpormedia.2024053135","url":null,"abstract":"In open-cell foams solid lumps are often present at the intersection of struts, known as the nodes. In this study models available in the literature that represent foams with solid accumulation at the nodes are investigated and used to obtain predictive equations for the permeability (for both the Darcy and Forchheimer flow regimes) and specific surface area for given porosity and average pore diameter values. The majority of the predictive equations proposed for the specific surface area based on these models are novel contributions. Furthermore, a method is proposed for incorporating solid lumps at the nodes into the existing foam (or three-strut) rectangular Representative Unit Cell (RUC) model. The models obtained from the literature along with the node adjusted RUC model are compared to one another and to relevant experimental data from the literature for foams that have accumulation of solid matter present at the nodes. The node adjusted RUC model provides physically meaningful and satisfactory changes to the specific surface area and permeability predictions of the existing foam RUC model.","PeriodicalId":50082,"journal":{"name":"Journal of Porous Media","volume":"12 2 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1615/jpormedia.2024049723
Jun Hu, Ya-Juan Dong, Zhi-Feng Liu, Jin-Biao Yu, Xiao-Hong Wang, Yong Wang
This article proposes an advanced nine-point (9P) scheme for solving multiphase flow in heterogeneous porous media, which is an extension of the 5P scheme constructed by the finite analytical method (FAM). As media heterogeneity increases, the error of traditional algorithms become uncontrollable due to their significant underestimation of nodal transmissibility. However, the transmissibility calculated in FAM is based on a local analytical solution and its accuracy is not dependent on the strength of heterogeneity. The proposed FAM-9P scheme offers two distinct advantages. Compared to the traditional 9P scheme, it provides much more accurate simulation results, especially for strongly heterogeneous porous media. Additionally, compared to the FAM-5P scheme, it can alleviate grid orientation effect (GOE) under adverse mobility ratios.
{"title":"An Advanced Nine-Point Scheme based on Finite Analysis in Two-Dimensional Numerical Reservoir Simulation","authors":"Jun Hu, Ya-Juan Dong, Zhi-Feng Liu, Jin-Biao Yu, Xiao-Hong Wang, Yong Wang","doi":"10.1615/jpormedia.2024049723","DOIUrl":"https://doi.org/10.1615/jpormedia.2024049723","url":null,"abstract":"This article proposes an advanced nine-point (9P) scheme for solving multiphase flow in heterogeneous porous media, which is an extension of the 5P scheme constructed by the finite analytical method (FAM). As media heterogeneity increases, the error of traditional algorithms become uncontrollable due to their significant underestimation of nodal transmissibility. However, the transmissibility calculated in FAM is based on a local analytical solution and its accuracy is not dependent on the strength of heterogeneity. The proposed FAM-9P scheme offers two distinct advantages. Compared to the traditional 9P scheme, it provides much more accurate simulation results, especially for strongly heterogeneous porous media. Additionally, compared to the FAM-5P scheme, it can alleviate grid orientation effect (GOE) under adverse mobility ratios.","PeriodicalId":50082,"journal":{"name":"Journal of Porous Media","volume":"2 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1615/jpormedia.2024049750
Hu Junlei, Guan Chong, Zheng Kuncan, Shi Qiangjun, Han Fulin, Chen Zhaodong
Flow resistance in porous media has been a challenging research topic in engineering and flow mechanics, plays an crucial role in industrial production and daily life. This paper presents the innovative five-sphere model by employing the capillary flow, pore-throat, flowing around models. The flow resistance of the five-sphere model incorporates capillary flow resistance, local resistance caused by the changes of pore-throat, and flowing around resistance of fluids around the filling material, which is summarized to derive a formula for the flow resistance of porous media without empirical parameters. Based on 42 sets of experimental data obtained from literature, this paper compares and validates the proposed model. When ,the five-sphere model is compared with the Carman equation, Ergun and WuJinsui equation; when , the comparison made with the Ergun and WuJinsui equation. Out of the 22 sets of data with deviations in the range of 0-30% of the five-sphere model equation for particles with an average diameter of 0.2 mm up to 56.8 mm; porosity ranging from 0.32 to 0.4174, superficial velocities ranging from 0.000038 m/s to 0.5342 m/s; and Reynolds number ranging from 0.124 to 10730. By further analysis of viscous and inertial resistance, it is found that viscous resistance losses from capillary flow and flowing around occupy the main part; when Rep < 30; inertial resistance losses from diameter change and flowing around occupy the main part when Rep > 150. This further confirms that flowing around occupies an important position in the flow resistance of porous media.
{"title":"Flow resistance study of porus media based on five-sphere model","authors":"Hu Junlei, Guan Chong, Zheng Kuncan, Shi Qiangjun, Han Fulin, Chen Zhaodong","doi":"10.1615/jpormedia.2024049750","DOIUrl":"https://doi.org/10.1615/jpormedia.2024049750","url":null,"abstract":"Flow resistance in porous media has been a challenging research topic in engineering and flow mechanics, plays an crucial role in industrial production and daily life. This paper presents the innovative five-sphere model by employing the capillary flow, pore-throat, flowing around models. The flow resistance of the five-sphere model incorporates capillary flow resistance, local resistance caused by the changes of pore-throat, and flowing around resistance of fluids around the filling material, which is summarized to derive a formula for the flow resistance of porous media without empirical parameters. Based on 42 sets of experimental data obtained from literature, this paper compares and validates the proposed model. When ,the five-sphere model is compared with the Carman equation, Ergun and WuJinsui equation; when , the comparison made with the Ergun and WuJinsui equation. Out of the 22 sets of data with deviations in the range of 0-30% of the five-sphere model equation for particles with an average diameter of 0.2 mm up to 56.8 mm; porosity ranging from 0.32 to 0.4174, superficial velocities ranging from 0.000038 m/s to 0.5342 m/s; and Reynolds number ranging from 0.124 to 10730. By further analysis of viscous and inertial resistance, it is found that viscous resistance losses from capillary flow and flowing around occupy the main part; when Rep < 30; inertial resistance losses from diameter change and flowing around occupy the main part when Rep > 150. This further confirms that flowing around occupies an important position in the flow resistance of porous media.","PeriodicalId":50082,"journal":{"name":"Journal of Porous Media","volume":"2 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1615/jpormedia.2024053343
Huijin Xu, MS Liu, ZF He
In this paper, an experimental study is performed to enhance the heat transfer ability of phase change material (PCM) using copper foam (CF). A numerical model is established to predict the melting and solidification process of composite phase change materials (CPCM) in metal foams. The step-cooling curve of CF/CPCM is ideal, with low subcooling and high thermal conductivity because of its interconnected porous structure and high thermal conductivity. the CF/CPCM physical parameters are in line with the expected target. Therefore, a more suitable solution should be selected for practical applications. The CF/CPCM heat storage and exothermic device basically completes the exothermic solidification process at 3600s, and basically completes the heat absorption and melting process at 4200s, which has a more obvious effect on the overall heat transfer strengthening of the device and reducing the non-uniformity of the material, and the design and construction of the CF/CPCM heat storage and exothermic device can be carried out when the application cost is possible.
{"title":"Heat Transfer Enhancement of Modified Sodium Acetate Trihydrate Composite Phase Change Material with Metal Foams","authors":"Huijin Xu, MS Liu, ZF He","doi":"10.1615/jpormedia.2024053343","DOIUrl":"https://doi.org/10.1615/jpormedia.2024053343","url":null,"abstract":"In this paper, an experimental study is performed to enhance the heat transfer ability of phase change material (PCM) using copper foam (CF). A numerical model is established to predict the melting and solidification process of composite phase change materials (CPCM) in metal foams. The step-cooling curve of CF/CPCM is ideal, with low subcooling and high thermal conductivity because of its interconnected porous structure and high thermal conductivity. the CF/CPCM physical parameters are in line with the expected target. Therefore, a more suitable solution should be selected for practical applications. The CF/CPCM heat storage and exothermic device basically completes the exothermic solidification process at 3600s, and basically completes the heat absorption and melting process at 4200s, which has a more obvious effect on the overall heat transfer strengthening of the device and reducing the non-uniformity of the material, and the design and construction of the CF/CPCM heat storage and exothermic device can be carried out when the application cost is possible.","PeriodicalId":50082,"journal":{"name":"Journal of Porous Media","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141942560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1615/jpormedia.2024053261
Umair Khan, Aurang Zaib, Anuar Ishak, El-Sayed M. Sherif, Ioan Pop
Drilling fluids are important in the extraction of oils and gases through rocks and soil. Clay nanoparticles are essential for enhancing drilling fluid efficiency. The thermal conductivity, viscosity, and boiling point of drilling fluids increase when clay nanoparticles are incorporated, providing resistance to high temperatures and regulating fluid costs. This article illustrates the convection heat transfer in drilling nanofluid while taking into account the significant presence of clay nanoparticles in the fluid used for drilling. The efficient thermophysical characteristics of clay nanofluid are expressed mathematically using Maxwell-Garnett and Brinkman's formulas. The linear PDEs with physical boundary conditions that control the flow phenomena are predetermined. The similarity technique is employed to transmute these PDEs into ODEs and then an efficient bvp4c solver is utilized to find dual solutions. The Nusselt number and skin friction are calculated and displayed in tabular form as well as graphical form along with the velocity and temperature profiles. Multiple solutions are observed in the case of shrinkable sheets as well as in the case of buoyancy assisting flow. The findings demonstrate that when volume concentration increases, the Nusselt number rises noticeably. In addition, the permeability parameter expands the boundary layer thickness in the lower solution, while the contrary behavior is observed in the upper solution.
{"title":"CONVECTIVE FLOW AND HEAT TRANSPORT OF CLAY NANOFLUID ACROSS A VERTICAL SURFACE IN A DARCY-BRINKMAN POROUS MEDIUM","authors":"Umair Khan, Aurang Zaib, Anuar Ishak, El-Sayed M. Sherif, Ioan Pop","doi":"10.1615/jpormedia.2024053261","DOIUrl":"https://doi.org/10.1615/jpormedia.2024053261","url":null,"abstract":"Drilling fluids are important in the extraction of oils and gases through rocks and soil. Clay nanoparticles are essential for enhancing drilling fluid efficiency. The thermal conductivity, viscosity, and boiling point of drilling fluids increase when clay nanoparticles are incorporated, providing resistance to high temperatures and regulating fluid costs. This article illustrates the convection heat transfer in drilling nanofluid while taking into account the significant presence of clay nanoparticles in the fluid used for drilling. The efficient thermophysical characteristics of clay nanofluid are expressed mathematically using Maxwell-Garnett and Brinkman's formulas. The linear PDEs with physical boundary conditions that control the flow phenomena are predetermined. The similarity technique is employed to transmute these PDEs into ODEs and then an efficient bvp4c solver is utilized to find dual solutions. The Nusselt number and skin friction are calculated and displayed in tabular form as well as graphical form along with the velocity and temperature profiles. Multiple solutions are observed in the case of shrinkable sheets as well as in the case of buoyancy assisting flow. The findings demonstrate that when volume concentration increases, the Nusselt number rises noticeably. In addition, the permeability parameter expands the boundary layer thickness in the lower solution, while the contrary behavior is observed in the upper solution.","PeriodicalId":50082,"journal":{"name":"Journal of Porous Media","volume":"36 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141942559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We are examining a mathematical model incorporating a heat conduction dual-phase-lags (DPL) model. One may use this model to examine how thermoelastic waves behave in a porous thermoelastic material. A modified version of the Christoffel equations is extracted from the model to investigate the propagation of harmonic plane waves. We next solve these equations to get the complex velocities of waves in the medium. Four waves appear in the medium, and the equations explain their existence and propagation. We find the correlations between the displacements of solid and fluid particles and the wave-induced temperature in the medium. The study considers the case of inhomogeneous wave propagation, defined by a complex slowness vector specification with a finite non-dimensional parameter indicating the inhomogeneity degree. Each of the four attenuated waves propagating inhomogeneously through the porous aggregate has its phase velocities and attenuation coefficients determined. We calculate the velocities and attenuation of the compressional and shear waves using a numerical model of liquid-saturated sandstone. Their fluctuations with thermal and poroelastic parameters are depicted visually.
{"title":"Inhomogeneous wave propagation in porothermoelastic medium with dual-phase-lag heat conduction","authors":"Manjeet Kumari, Priyanka Lather, Neelam Kumari, Pradeep Kaswan, Manjeet Kumar","doi":"10.1615/jpormedia.2024053065","DOIUrl":"https://doi.org/10.1615/jpormedia.2024053065","url":null,"abstract":"We are examining a mathematical model incorporating a heat conduction dual-phase-lags (DPL) model. One may use this model to examine how thermoelastic waves behave in a porous thermoelastic material. A modified version of the Christoffel equations is extracted from the model to investigate the propagation of harmonic plane waves. We next solve these equations to get the complex velocities of waves in the medium. Four waves appear in the medium, and the equations explain their existence and propagation. We find the correlations between the displacements of solid and fluid particles and the wave-induced temperature in the medium. The study considers the case of inhomogeneous wave propagation, defined by a complex slowness vector specification with a finite non-dimensional parameter indicating the inhomogeneity degree. Each of the four attenuated waves propagating inhomogeneously through the porous aggregate has its phase velocities and attenuation coefficients determined. We calculate the velocities and attenuation of the compressional and shear waves using a numerical model of liquid-saturated sandstone. Their fluctuations with thermal and poroelastic parameters are depicted visually.","PeriodicalId":50082,"journal":{"name":"Journal of Porous Media","volume":"60 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1615/jpormedia.2024052876
Hamid-Reza Bahrami, Mahdi Mohseni
This research investigates the thermal performance of a helically coiled tube filled with a porous material. The study uses numerical simulations over a wide range of Reynolds and Darcy numbers. The porous materials used are steel, aluminum, and copper. To determine the contribution of porous material as well as the spiraling effects of the pipe to increased heat transfer, the simulations were also run for a helical coil without porous material and a porous-filled straight tube. The pitch and radius of the coil were varied, resulting in different coil turns for a given length of the pipe. The rate of exergy destruction in different states was calculated to determine the optimal operating point of the system. The study reveals that porous material significantly improves heat transfer in both straight and helical tubes. The optimal performance is achieved at higher Darcy numbers, with heat transfer being independent or dependent on Re. The highest Nu value is around 450 at Da=0.1 and Re=2000, about 103 times and 17 times the Nu in the straight and helical tubes without porous material, respectively. However, the peak value of PEC is 2 and 17 with respect to porous-filled straight tubes and non-porous helical coils. The main achievement of this study is that it shows that porous media can be applied to amplify heat transfer beside the secondary flow in helical tubes under specific conditions. This enhancement occurs when using porous media with high Da numbers, such as Da ~ 0.1. In contrast, the study shows that using porous media with low permeability (Da ~ 0.0001) surpasses secondary flows effects where the thermal performances of porous filled helical tubes and straight t
这项研究调查了充满多孔材料的螺旋卷管的热性能。研究采用数值模拟的方法，在很大的雷诺数和达西数范围内进行。使用的多孔材料有钢、铝和铜。为了确定多孔材料的贡献以及管道的螺旋效应对增加传热的影响，还对无多孔材料的螺旋盘管和充满多孔材料的直管进行了模拟。线圈的间距和半径不同，导致给定长度管道的线圈匝数不同。通过计算不同状态下的能量损耗率，确定了系统的最佳运行点。研究表明，多孔材料能显著改善直管和螺旋管的传热效果。最佳性能在达西数较高时实现，传热与 Re 无关或相关。在 Da=0.1 和 Re=2000 时，最高 Nu 值约为 450，分别是无多孔材料直管和螺旋管中 Nu 值的 103 倍和 17 倍。然而，多孔填充直管和无孔螺旋线圈的 PEC 峰值分别为 2 和 17。这项研究的主要成果表明，在特定条件下，多孔介质可用于放大螺旋管中二次流旁的传热。当使用高 Da 数（如 Da ~ 0.1）的多孔介质时，这种增强作用就会出现。与此相反，研究表明，使用低渗透率（Da ~ 0.0001）的多孔介质可以超越二次流的效果，在这种情况下，多孔填充螺旋管和直管的热性能都会有所提高。
{"title":"Exploring Impacts of Using Porous Media on Heat Transfer in Helical Coils: A Comprehensive Numerical Study","authors":"Hamid-Reza Bahrami, Mahdi Mohseni","doi":"10.1615/jpormedia.2024052876","DOIUrl":"https://doi.org/10.1615/jpormedia.2024052876","url":null,"abstract":"This research investigates the thermal performance of a helically coiled tube filled with a porous material. The study uses numerical simulations over a wide range of Reynolds and Darcy numbers. The porous materials used are steel, aluminum, and copper. To determine the contribution of porous material as well as the spiraling effects of the pipe to increased heat transfer, the simulations were also run for a helical coil without porous material and a porous-filled straight tube. The pitch and radius of the coil were varied, resulting in different coil turns for a given length of the pipe. The rate of exergy destruction in different states was calculated to determine the optimal operating point of the system. The study reveals that porous material significantly improves heat transfer in both straight and helical tubes. The optimal performance is achieved at higher Darcy numbers, with heat transfer being independent or dependent on Re. The highest Nu value is around 450 at Da=0.1 and Re=2000, about 103 times and 17 times the Nu in the straight and helical tubes without porous material, respectively. However, the peak value of PEC is 2 and 17 with respect to porous-filled straight tubes and non-porous helical coils. The main achievement of this study is that it shows that porous media can be applied to amplify heat transfer beside the secondary flow in helical tubes under specific conditions. This enhancement occurs when using porous media with high Da numbers, such as Da ~ 0.1. In contrast, the study shows that using porous media with low permeability (Da ~ 0.0001) surpasses secondary flows effects where the thermal performances of porous filled helical tubes and straight t","PeriodicalId":50082,"journal":{"name":"Journal of Porous Media","volume":"28 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil salinization is considered among the most serious problems that affect irrigated lands and, thus, food security in the world. It is interesting to develop methods to test soil salinization. In this paper, the electric properties of sand-salt crystals (NaCl) mixtures (SSM) are investigated using electrical impedance spectroscopy. Seven samples were considered by mixing dry sand and salt crystals with different salt mass percentages (SMP) from 0% to 100%. The electrical responses are explored by measuring the electrical impedance and the global conductance for different SSM filling a small capacitive cell. The influence of frequency and SMP on the electrical conductance and the complex impedance are investigated. It was found that the conductance shows high dispersion with SMP at the whole frequency range and a high dispersion with frequency at low and high frequencies (≤103Hz and ≥105Hz). Impedance diagrams show a frequency dispersion at high and low frequencies that is modeled by an equivalent circuit constituted of three dipoles in series, each one formed by a pure resistance and a constant phase element in parallel. Findings characteristics are directly related to the rate of salt crystals in the samples. Then, the method developed in this work constitutes a non-destructive technique for detecting salt crystals in soils in arid regions and can be used to develop devices for in situ measurements.
{"title":"Characterization of salt crystals in soil using electrochemical measurements","authors":"Ferid Mezdari, Walaeddine Maaoui, Faycel Tiss, Mustapha Najjari, Kamel Khirouni, Noureddine Hamdi","doi":"10.1615/jpormedia.2024052860","DOIUrl":"https://doi.org/10.1615/jpormedia.2024052860","url":null,"abstract":"Soil salinization is considered among the most serious problems that affect irrigated lands and, thus, food security in the world. It is interesting to develop methods to test soil salinization. In this paper, the electric properties of sand-salt crystals (NaCl) mixtures (SSM) are investigated using electrical impedance spectroscopy. Seven samples were considered by mixing dry sand and salt crystals with different salt mass percentages (SMP) from 0% to 100%. The electrical responses are explored by measuring the electrical impedance and the global conductance for different SSM filling a small capacitive cell. The influence of frequency and SMP on the electrical conductance and the complex impedance are investigated. It was found that the conductance shows high dispersion with SMP at the whole frequency range and a high dispersion with frequency at low and high frequencies (≤103Hz and ≥105Hz). Impedance diagrams show a frequency dispersion at high and low frequencies that is modeled by an equivalent circuit constituted of three dipoles in series, each one formed by a pure resistance and a constant phase element in parallel. Findings characteristics are directly related to the rate of salt crystals in the samples. Then, the method developed in this work constitutes a non-destructive technique for detecting salt crystals in soils in arid regions and can be used to develop devices for in situ measurements.","PeriodicalId":50082,"journal":{"name":"Journal of Porous Media","volume":"77 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141784136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1615/jpormedia.2024053606
Mingjing Lu, Yuegang Wang
Shale oil reservoirs are characterized by dense, extremely low permeability, and poorly developed natural fractures, and hydraulic fracturing technology is often used in extraction to improve recovery. It is significant to clarify the mechanism and influence mechanism of the displacement in complex porous media coupled with fractures and matrix to enhance oil recovery. In this study, based on the lattice Boltzmann method utilizing the fracture-matrix pore coupling model, the authors carried out a study of displacement in organic and inorganic pore space and systematically investigated the influence mechanisms of wettability and Ca on the crude oil recovery rate. It was found that the stronger the wettability of the water phase, the higher the crude oil recovery rate, and the lower the residual oil in the form of adsorbed oil film; and the larger the Capillary numbers, the higher the crude oil recovery rate. Crude oil in organic pore space is more difficult to discharge compared with that in inorganic pore space, and the recovery rate of crude oil in organic pore space can be effectively improved by increasing the driving pressure and enhancing the properties of the water phase (fracturing fluid).
页岩油藏的特点是致密、渗透率极低、天然裂缝不发育，在开采中通常采用水力压裂技术提高采收率。阐明裂缝与基质耦合的复杂多孔介质中位移的机理和影响机制对提高石油采收率意义重大。在这项研究中，作者基于晶格玻尔兹曼法，利用裂缝-基质孔隙耦合模型，开展了有机和无机孔隙空间位移研究，系统研究了润湿性和 Ca 对原油采收率的影响机理。研究发现，水相润湿性越强，原油采收率越高，以吸附油膜形式存在的残油越少；毛细管数越大，原油采收率越高。有机孔隙中的原油比无机孔隙中的原油更难排出，通过增加驱动压力和提高水相（压裂液）的性能，可以有效提高有机孔隙中的原油采收率。
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