Article
Thermodynamics
Xinjian Chen, Junwei Li, Xu He, Dan Zhao, Ningfei Wang
Summary: This paper investigates the effects of ordered porous ceramics and pore size on the stability, thermal performance, and emission performance of meso-scale burners. The results show that ordered porous ceramics enhance heat transfer, reduce NOx emissions, and have potential applications in micro thermoelectric and thermophotovoltaic systems.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Qingyu Yang, Yingying Yang, Kai Zhang, Majdi Azaiez
Summary: This study investigates the freezing mechanisms of water in porous media at the pore scale using a combination of experimental and numerical approaches. The results show that the evolution of the phase interface and temperature gradient in the pore vary under different thermal conductivity conditions.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Engineering, Environmental
Ishaan Markale, Gabriele M. Cimmarusti, Melanie M. Britton, Joaquin Jimenez-Martinez
Summary: This study uses MRI to obtain 3D images and investigates the impact of phase saturation on mixing and reactions, explaining the faster than Fickian rate of product formation. The results show that as saturation increases, the product formation also increases.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Environmental Sciences
Rui Wang, Maziar Arshadi, Ahmed Zankoor, Mohammad Piri
Summary: Pore space deformation can significantly affect the behavior of multiphase flow through porous media, leading to changes in permeability, relative permeability, and fluid distributions. However, the mechanisms relating pore-level fluid displacements with pore space deformation are not well understood. In this study, we conducted two-phase flow experiments on a water-wet sandpack under different stress conditions while imaging the pore space and fluid configurations. The results showed that pore space contraction influenced the frequency of different fluid displacement mechanisms and also affected the saturation and distribution of the fluids. The study also revealed that wetting and non-wetting phases responded differently to pore space deformation, resulting in changes in relative permeabilities.
WATER RESOURCES RESEARCH
(2022)
Article
Engineering, Mechanical
Thien Nguyen, Stephen King, Yassin Hassan
Summary: The study experimentally investigated the flow mixing and turbulence characteristics in pore-scale regions of porous media or randomly packed beds, revealing different and complex flow patterns in different pore regions. The results showed highly turbulent mixing regions at the pore centers and low-velocity or stagnation-flow regions near the sphere surfaces in pore regions, with complex interactions among jet flows discharging into the pores.
EXPERIMENTS IN FLUIDS
(2021)
Article
Mechanics
Chunendra K. Sahu, Jerome A. Neufeld
Summary: This study investigates the effects of heterogeneity of permeability in porous media on density-driven flows. Laboratory experiments show that the mixing in heterogeneous media can be significantly greater than in homogeneous media of similar properties. This enhanced mixing is primarily due to the layered structure, which results in transverse gravity-driven fingers and a blunt front.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Timan Lei, Kai H. Luo
Summary: The study reveals that dissolution reaction can delay the onset of fingering and affect fingering propagation and intensity, demonstrating the complex interplay between dissolution, diffusion, and viscosity contrast during miscible displacement in porous media. Increasing Peclet number and viscosity ratio destabilize fingering, while increasing Damkohler number can first suppress and then intensify fingering. The findings provide insights into displacement stability during geological CO2 sequestration, aiding in evaluating storage efficiency and safety.
Article
Water Resources
Milad Hosseini, Majid Siavashi, Milad Shirbani, Mohaddeseh Mousavi Nezhad
Summary: Simulation of flow at the pore scale is crucial for understanding fluid behavior in porous media. This study investigates the effect of the magic parameter on simulation results by considering errors in micro-CT images, and compares the results with the Navier-Stokes method. The study also presents a criterion for estimating the error amplitude of flow characteristics due to micro-CT imaging. The findings show that the magic parameter can accurately simulate complex geometries with minimal error.
ADVANCES IN WATER RESOURCES
(2023)
Review
Thermodynamics
Li Chen, An He, Jianlin Zhao, Qinjun Kang, Zeng-Yao Li, Jan Carmeliet, Naoki Shikazono, Wen-Quan Tao
Summary: This review summarizes the recent advances and challenges in pore-scale modeling, discussing its practical applications in geoscience, polymer exchange membrane fuel cells, and solid oxide fuel cells. Notable results from pore-scale modeling are presented, while the challenges facing the development of pore-scale models are also discussed.
PROGRESS IN ENERGY AND COMBUSTION SCIENCE
(2022)
Article
Thermodynamics
Yang Liu, Yangbo Deng, Junrui Shi, Tingting Yan, Zhenyu Min, Bingquan Ge
Summary: This study uses numerical simulation to investigate the non-equilibrium characteristics of gas velocity and temperature in a two-layer porous media burner, showing that the extent of flow non-equilibrium increases with increasing inlet velocity and equivalence ratio, while gas temperature non-equilibrium decreases slightly with inlet velocity.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Engineering, Aerospace
Wenjie Kong, Hao Dong, Jie Wu, Yidi Zhao, Zhou Jin
Summary: Through experimental observation, we found that porous media with different pore densities have different effects on the aerodynamic performance of the airfoil. Although the porous media with 20PPI increased the pressure drag and reduced the lift, it considerably reduced the friction drag, thus significantly improving the aerodynamic force of the airfoil.
Article
Energy & Fuels
Xinjian Chen, Junwei Li, Dan Zhao, Anchen Song, Xinyuan Zhou, Ningfei Wang
Summary: Experimental observations showed that flames in porous media exhibit pulsating propagation, with the increase in pore density affecting both the maximum speed and average speed of the flame. The flame speed is primarily influenced by the wall quenching and heat recirculation effects.
Article
Thermodynamics
Muhammad Nasir, Kazuki Kaito, Anindityo Patmonoaji, Mohammad Azis Mahardika, Yun She, Shintaro Matsushita, Tetsuya Suekane
Summary: X-ray micro-tomography was used to study the pore-scale drying process and characterize the liquid film region and the invasion front. The decrease in saturation is not uniform across the pore size. The invasion front shows a sharp decrease in liquid saturation and the presence of liquid film and multi-pore connected clusters.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Yingxue Hu, Anindityo Patmonoaji, Haiping Xu, Kazuki Kaito, Shintaro Matsushita, Tetsuya Suekane
Summary: Fluid-fluid interphase mass transfer in porous media is crucial for soil and groundwater remediation. Experimental studies revealed the dynamics of dissolution process and the impact of pore structure on entrapped NAPL. Results showed that the mass transfer coefficient is independent of concentration difference and the 3D packed bed had a higher overall mass transfer coefficient under Darcy flow conditions.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Environmental Sciences
Shuaibing Song, Ming Li, Qingyi Tu, Anying Yuan, Zhenhua Jiao, Pan Li, Wenxin Qian, Hewu Liu, Nan Xu
Summary: An improved universal fusion algorithm for constructing three-dimensional multiscale porous media was proposed and successfully applied to carbonate rock, sandstone, and coal, with their absolute permeability calculated using the finite element method. The results showed that the improved fusion algorithm effectively reduced pore bias and maintained good pore interconnectivity, with a wider pore size distribution interval and closer absolute permeability values to laboratory measurements compared to the existing algorithm.
WATER RESOURCES RESEARCH
(2021)
Article
Engineering, Chemical
Alejandro Fernandez Visentini, Pietro de Anna, Damien Jougnot, Tanguy Le Borgne, Yves Meheust, Niklas Linde
Summary: This study investigates the impact of diffusion-limited mixing on bulk electrical conductivity in a porous medium with layered solute concentration distribution. The results reveal that the electrical data correlate well with time-series of solute mixing descriptors.
TRANSPORT IN POROUS MEDIA
(2023)
Review
Biotechnology & Applied Microbiology
Joaquin Jimenez-Martinez, Jen Nguyen, Dani Or
Summary: This article introduces the biomineralization process of microorganisms in porous media and discusses how various factors interact to affect biomineralization. Studying the behavior of microorganisms in complex microenvironments can promote the understanding of natural systems and the development of technological applications.
REVIEWS IN ENVIRONMENTAL SCIENCE AND BIO-TECHNOLOGY
(2022)
Article
Engineering, Chemical
Ishaan Markale, Andres Velasquez-Parra, Andres Alcolea, Joaquin Jimenez-Martinez
Summary: This study explores the adsorption mechanisms in unsaturated systems by analyzing flow, transport, and adsorption processes under different liquid saturation degrees through experimental and numerical simulation approaches. The results show that as the liquid saturation decreases, the mixing increases and the adsorbed mass reduces. The adsorption exhibits a nonlinear relationship with the liquid saturation, which can be attributed to the nonlinear variation of the volume fraction of the liquid phase.
TRANSPORT IN POROUS MEDIA
(2023)
Article
Engineering, Chemical
Lazaro J. Perez, Alexandre Puyguiraud, Juan J. Hidalgo, Joaquin Jimenez-Martinez, Rishi Parashar, Marco Dentz
Summary: We study mixing-controlled chemical reactions in unsaturated porous media from a pore-scale perspective. The results show that there is a significant increase in reactive mixing for decreasing saturation, which is caused by the stronger heterogeneity of the water phase and flow field.
TRANSPORT IN POROUS MEDIA
(2023)
Article
Engineering, Chemical
Mayumi Hamada, Pietro de Anna
Summary: Molecular diffusion plays a crucial role in various systems and often limits the rate of biological or chemical reactions. This article proposes a novel method to directly measure the diffusion coefficient of solutes or suspensions in liquids. Unlike existing methods, this new method does not rely on prior knowledge of fluid or tracer properties but uses optical techniques to directly measure the concentration spatial profile of the tracer. The technique is validated by measuring the diffusion coefficient of both spherical and non-spherical tracers, and the importance of considering the finite size of the diffusion chamber for proper estimation of diffusion coefficient and mixing degree is demonstrated.
TRANSPORT IN POROUS MEDIA
(2023)
Article
Mechanics
Shabina Ashraf, Yves Meheust, Jyoti Phirani
Summary: This study proposes a model based on interacting capillaries to predict the spontaneous imbibition in quasi-two-dimensional porous media. The breakthrough time, wetting fluid saturation, and leading meniscus are determined by the capillaries' radii distribution and spatial arrangement. The model provides accurate predictions for the position in time of the saturating front and the leading visible front.
Article
Environmental Sciences
Ilan Ben-Noah, J. J. Hidalgo, Joaquin Jimenez-Martinez, Marco Dentz
Summary: In this study, the upscaling of pore-scale solute transport in partially saturated porous media at different saturation degrees was investigated. It was found that the interaction between structural heterogeneity, phases distribution, and small-scale flow dynamics leads to complex flow patterns and broad probability distributions of flow. A continuous-time random walk (CTRW) framework was used to upscale and evaluate the transport of diluted solutes, and the results were compared to direct numerical simulations. The analysis showed that the fluid phase saturation, as well as the Peclet number, influenced the advective tortuosity, characteristic length, fraction of immobile region, mean trapping time, trapping length, and trapping frequency.
WATER RESOURCES RESEARCH
(2023)
Article
Engineering, Environmental
Dorothee L. Kurz, Eleonora Secchi, Roman Stocker, Joaquin Jimenez-Martinez
Summary: The functioning of natural and engineered porous media relies on the interplay between biochemical processes and hydrodynamics. In such environments, biofilms often form, altering the distribution of fluid flow velocities and affecting their permeability. However, the control of biofilm clustering and resulting permeability heterogeneity is not well understood, limiting predictive abilities for biofilm-porous medium systems.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Ishaan Markale, Maxence Carrel, Dorothee L. Kurz, VeronicaL. Morales, Markus Holzner, Joaquin Jimenez-Martinez
Summary: Internal heterogeneity of biofilms plays a crucial role in enhancing fluid mixing and reactions within porous media, which has significant implications for industrial and environmental applications. This study utilizes advanced imaging techniques to investigate the impact of internal heterogeneity on fluid flow and solute transport in bacterial biofilms. The results show that internal heterogeneity mainly affects intermediate velocities and significantly influences biologically driven reactions. Understanding and considering the internal heterogeneity of biofilms is important for predicting reactivity in bioclogged porous systems.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Oshri Borgman, Regis Turuban, Baudouin Geraud, Tanguy Le Borgne, Yves Meheust
Summary: In subsurface environments, incomplete mixing at the pore scale limits reaction rates, making it difficult to predict them using Darcy-scale models. Pore-scale concentration gradients are enhanced by the deformation of solute fronts and decay under molecular diffusion and solute filament merging. However, the dependence of concentration gradient dynamics on flow rates is still unclear. This study experimentally measures pore-scale concentrations in solute fronts and reveals that pore-scale shear flow increases concentration gradients up to a predicted time, but the flow rate-dependency of the mean concentration gradient is weaker than expected due to lamellae aggregation.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Multidisciplinary Sciences
Alon Nissan, Uria Alcolombri, Nadav Peleg, Nir Galili, Joaquin Jimenez-Martinez, Peter Molnar, Markus Holzner
Summary: The role of soil in Earth's carbon budget is uncertain. A new model shows that soil temperature and moisture are linked to global soil respiration. Heterotrophic respiration has been increasing by 2% per decade since the 1980s, and it is projected to increase by 40% by the end of the century. Soil carbon efflux is the largest terrestrial carbon source to the atmosphere, but it remains one of the most uncertain fluxes in the global carbon budget.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Nafiseh Salehi Siavashani, Javier Valdes-Abellan, Frederic Do, Joaquin Jimenez-Martinez, F. Javier Elorza, Lucila Candela, Aleix Serrat-Capdevila
Summary: The Chari-Baguirmi region in Africa has a naturally occurring piezometric depression with deeper than expected groundwater levels. The lack of rainwater infiltration and exfiltration processes, past climate conditions, and geological structural constraints explain the origin and dynamics of this depressed area. Numerical simulations show that the rainfall effect is limited to upper soil layers, resulting in low aquifer recharge.
ENVIRONMENTAL EARTH SCIENCES
(2023)
Article
Geosciences, Multidisciplinary
Joaquin Jimenez-Martinez
Summary: Field-based learning in hydrogeology helps students develop practical understanding and application skills, as well as enhance generic skills. However, there are cognitive difficulties in teaching and learning hydrogeology, especially in the field. To facilitate students' transition from mental to conceptual models, it is important to address prior misconceptions and provide methods for integrating new information.
Article
Environmental Sciences
Satoshi Izumoto, Joris Heyman, Johan Alexander Huisman, Kevin De Vriendt, Cyprien Soulaine, Francesco Gomez, Herve Tabuteau, Yves Meheust, Tanguy Le Borgne
Summary: Mixing fronts at the interface of opposing flows are compressed at a constant rate, leading to enhanced chemical gradients and biogeochemical processes. This study investigates how fluid compression controls the amplitude of mixing and reaction rates in porous media. The experimental and numerical results provide new insights into the dynamics of mixing-induced reactions in porous media.
WATER RESOURCES RESEARCH
(2023)