Aqueous two-phase system features with ultralow interfacial tension and thick interfacial region,affording unique confined space for membrane assembly.Here,for the first time,an aqueous two-phase interfacial assembly ...Aqueous two-phase system features with ultralow interfacial tension and thick interfacial region,affording unique confined space for membrane assembly.Here,for the first time,an aqueous two-phase interfacial assembly method is proposed to fabricate covalent organic framework(COF)membranes.The aqueous solution containing polyethylene glycol and dextran undergoes segregated phase separation into two water-rich phases.By respectively distributing aldehyde and amine monomers into two aqueous phases,a series of COF membranes are fabricated at water-water interface.The resultant membranes exhibit high NaCl rejection of 93.0-93.6% and water permeance reaching 1.7-3.7 L m^(−2) h^(−1) bar^(−1),superior to most water desalination membranes.Interestingly,the interfacial tension is found to have pronounced effect on membrane structures.The appropriate interfacial tension range(0.1-1.0 mN m^(−1))leads to the tight and intact COF membranes.Furthermore,the method is extended to the fabrication of other COF and metal-organic polymer membranes.This work is the first exploitation of fabricating membranes in all-aqueous system,confering a green and generic method for advanced membrane manufacturing.展开更多
Cleat serves as the primary flow pathway for coalbed methane(CBM)and water.However,few studies consider the impact of local contact on two-phase flow within cleats.A visual generalized model of endogenous cleats was c...Cleat serves as the primary flow pathway for coalbed methane(CBM)and water.However,few studies consider the impact of local contact on two-phase flow within cleats.A visual generalized model of endogenous cleats was constructed based on microfluidics.A microscopic and mesoscopic observation technique was proposed to simultaneously capture gas-liquid interface morphology of pores and throat and the two-phase flow characteristics in entire cleat system.The local contact characteristics of cleats reduced absolute permeability,which resulted in a sharp increase in the starting pressure.The reduced gas flow capacity narrowed the co-infiltration area and decreased water saturation at the isotonic point in a hydrophilic environment.The increased local contact area of cleats weakened gas phase flow capacity and narrowed the co-infiltration area.Jumping events occurred in methane-water flow due to altered porosity caused by local contact in cleats.The distribution of residual phases changed the jumping direction on the micro-scale as well as the dominant channel on the mesoscale.Besides,jumping events caused additional energy dissipation,which was ignored in traditional two-phase flow models.This might contribute to the overestimation of relative permeability.The work provides new methods and insights for investigating unsaturated flow in complex porous media.展开更多
Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to ...Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to pipeline-riser flow needs evaluation since the flow condition in pipeline-riser is quite different from the original data where they were derived from. In the present study, a comprehensive evaluation of 24prevailing correlation in predicting frictional pressure drop is carried out based on experimentally measured data of air-water and air-oil two-phase flows in pipeline-riser. Experiments are performed in a system having different configuration of pipeline-riser with the inclination of the downcomer varied from-2°to-5°to investigated the effect of the elbow on the frictional pressure drop in the riser. The inlet gas velocity ranges from 0.03 to 6.2 m/s, and liquid velocity varies from 0.02 to 1.3 m/s. A total of885 experimental data points including 782 on air-water flows and 103 on air-oil flows are obtained and used to access the prediction ability of the correlations. Comparison of the predicted results with the measured data indicate that a majority of the investigated correlations under-predict the pressure drop on severe slugging. The result of this study highlights the requirement of new method considering the effect of pipe layout on the frictional pressure drop.展开更多
Understanding fingering, as a challenge to stable displacement during the immiscible flow, has become a crucial phenomenon for geological carbon sequestration, enhanced oil recovery, and groundwater protection. Typica...Understanding fingering, as a challenge to stable displacement during the immiscible flow, has become a crucial phenomenon for geological carbon sequestration, enhanced oil recovery, and groundwater protection. Typically governed by gravity, viscous and capillary forces, these factors lead invasive fluids to occupy pore space irregularly and incompletely. Previous studies have demonstrated capillary numbers,describing the viscous and capillary forces, to quantificationally induce evolution of invasion patterns.While the evolution mechanisms of invasive patterns have not been deeply elucidated under the constant capillary number and three variable parameters including velocity, viscosity, and interfacial tension.Our research employs two horizontal visualization systems and a two-phase laminar flow simulation to investigate the tendency of invasive pattern transition by various parameters at the pore scale. We showed that increasing invasive viscosity or reducing interfacial tension in a homogeneous pore space significantly enhanced sweep efficiency, under constant capillary number. Additionally, in the fingering crossover pattern, the region near the inlet was prone to capillary fingering with multi-directional invasion, while the viscous fingering with unidirectional invasion was more susceptible occurred in the region near the outlet. Furthermore, increasing invasive viscosity or decreasing invasive velocity and interfacial tension promoted the extension of viscous fingering from the outlet to the inlet, presenting that the subsequent invasive fluid flows toward the outlet. In the case of invasive trunk along a unidirectional path, the invasive flow increased exponentially closer to the outlet, resulting in a significant decrease in the width of the invasive interface. Our work holds promising applications for optimizing invasive patterns in heterogeneous porous media.展开更多
Polymer flooding in fractured wells has been extensively applied in oilfields to enhance oil recovery.In contrast to water,polymer solution exhibits non-Newtonian and nonlinear behavior such as effects of shear thinni...Polymer flooding in fractured wells has been extensively applied in oilfields to enhance oil recovery.In contrast to water,polymer solution exhibits non-Newtonian and nonlinear behavior such as effects of shear thinning and shear thickening,polymer convection,diffusion,adsorption retention,inaccessible pore volume and reduced effective permeability.Meanwhile,the flux density and fracture conductivity along the hydraulic fracture are generally non-uniform due to the effects of pressure distribution,formation damage,and proppant breakage.In this paper,we present an oil-water two-phase flow model that captures these complex non-Newtonian and nonlinear behavior,and non-uniform fracture characteristics in fractured polymer flooding.The hydraulic fracture is firstly divided into two parts:high-conductivity fracture near the wellbore and low-conductivity fracture in the far-wellbore section.A hybrid grid system,including perpendicular bisection(PEBI)and Cartesian grid,is applied to discrete the partial differential flow equations,and the local grid refinement method is applied in the near-wellbore region to accurately calculate the pressure distribution and shear rate of polymer solution.The combination of polymer behavior characterizations and numerical flow simulations are applied,resulting in the calculation for the distribution of water saturation,polymer concentration and reservoir pressure.Compared with the polymer flooding well with uniform fracture conductivity,this non-uniform fracture conductivity model exhibits the larger pressure difference,and the shorter bilinear flow period due to the decrease of fracture flow ability in the far-wellbore section.The field case of the fall-off test demonstrates that the proposed method characterizes fracture characteristics more accurately,and yields fracture half-lengths that better match engineering reality,enabling a quantitative segmented characterization of the near-wellbore section with high fracture conductivity and the far-wellbore section with low fracture conductivity.The novelty of this paper is the analysis of pressure performances caused by the fracture dynamics and polymer rheology,as well as an analysis method that derives formation and fracture parameters based on the pressure and its derivative curves.展开更多
Based on the displacement discontinuity method and the discrete fracture unified pipe network model,a sequential iterative numerical method was used to build a fracturing-production integrated numerical model of shale...Based on the displacement discontinuity method and the discrete fracture unified pipe network model,a sequential iterative numerical method was used to build a fracturing-production integrated numerical model of shale gas well considering the two-phase flow of gas and water.The model accounts for the influence of natural fractures and matrix properties on the fracturing process and directly applies post-fracturing formation pressure and water saturation distribution to subsequent well shut-in and production simulation,allowing for a more accurate fracturing-production integrated simulation.The results show that the reservoir physical properties have great impacts on fracture propagation,and the reasonable prediction of formation pressure and reservoir fluid distribution after the fracturing is critical to accurately predict the gas and fluid production of the shale gas wells.Compared with the conventional method,the proposed model can more accurately simulate the water and gas production by considering the impact of fracturing on both matrix pressure and water saturation.The established model is applied to the integrated fracturing-production simulation of practical horizontal shale gas wells.The simulation results are in good agreement with the practical production data,thus verifying the accuracy of the model.展开更多
Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement m...Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics devices.In this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) RMFs.In order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this model.It is found that the exothermal reaction in RMFs improved the ignition performance of SCB.In the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low temperature.In addition,it made up for pressure loss in the gas phase.During the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise continuously.This result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.展开更多
Aqueous zinc-halogen batteries are promising candidates for large-scale energy storage due to their abundant resources,intrinsic safety,and high theoretical capacity.Nevertheless,the uncontrollable zinc dendrite growt...Aqueous zinc-halogen batteries are promising candidates for large-scale energy storage due to their abundant resources,intrinsic safety,and high theoretical capacity.Nevertheless,the uncontrollable zinc dendrite growth and spontaneous shuttle effect of active species have prohibited their practical implementation.Herein,a double-layered protective film based on zinc-ethylenediamine tetramethylene phosphonic acid(ZEA)artificial film and ZnF2-rich solid electrolyte interphase(SEI)layer has been successfully fabricated on the zinc metal anode via electrode/electrolyte synergistic optimization.The ZEA-based artificial film shows strong affinity for the ZnF2-rich SEI layer,therefore effectively suppressing the SEI breakage and facilitating the construction of double-layered protective film on the zinc metal anode.Such double-layered architecture not only modulates Zn2+flux and suppresses the zinc dendrite growth,but also blocks the direct contact between the metal anode and electrolyte,thus mitigating the corrosion from the active species.When employing optimized metal anodes and electrolytes,the as-developed zinc-(dual)halogen batteries present high areal capacity and satisfactory cycling stability.This work provides a new avenue for developing aqueous zinc-(dual)halogen batteries.展开更多
Aqueous Zn-ion batteries have attracted much attention due to their unique high safety and low-cost merits.However,their practical applications are at a slow pace due to their short cycle life,which fundamentally resu...Aqueous Zn-ion batteries have attracted much attention due to their unique high safety and low-cost merits.However,their practical applications are at a slow pace due to their short cycle life,which fundamentally results from the instability of the positive/negative electrode interface in the traditional dilute aqueous electrolytes with high water activity.Developing highly concentrated electrolyte(HCE)has been considered as an effective solution.Unlike previous studies of single salt-based HCE(SSHCE),herein,a new dual-salt HCE(15 m ZnCl_(2)+10 m NH_(4)NH_(2)SO_(3)DS-HCE)was proposed for the first time.DS-HCE was proven to simultaneously possess higher conductivity than traditional dilute electrolytes and ultralow water activity of SS-HCE by the regulation of dual high-concentration salts on the solvation structure,which renders the Zn‖Zn symmetric cell the record-long cycling life of 2200 h compared with those with SS-HCE(30 m ZnCl_(2),300 h)and other reported HCEs.Additionally,the Zn‖NH_(4)V_(4)O_(10)full cell with DS-HCE demonstrated impressed rate capability within a wide-range current densities from 0.1 to 10 A g^(-1).Moreover,at the high current density of 5 A g^(-1),the full cell shows almost100%capacity retention after 4000 cycles,which indicates the promising future of the DS-HCE system for long-duration aqueous Zn-ion batteries.展开更多
Aqueous zinc-ion batteries encounter enormous challenges such as Zn dendrites and parasitic reactions.Separator modification is a highly effective strategy to address these issues.With the advantages of low cost,nonto...Aqueous zinc-ion batteries encounter enormous challenges such as Zn dendrites and parasitic reactions.Separator modification is a highly effective strategy to address these issues.With the advantages of low cost,nontoxicity,biodegradability,good film-forming ability,superior hydro phi licity,and rich functional groups,chitosan is an ideal matrix for constructing separators.However,the presence of positive charges within chitosan in weakly acidic electrolytes is unfavorable for dendrite inhibition.Herein,Schiff base reaction is introduced to modify chitosan matrix,transforming its charge polarity from positive to negative.Additionally,NbN with excellent zincophilicity is coated onto chitosan matrix,forming a Janus separator with low thickness of 19μm and considerably improved mechanical properties.The resultant separator can promote the transport of Zn^(2+)ions while triggering a repulsive shielding effect against anions,therefore dramatically enhancing Zn^(2+)ion transfer number from 0.28 to 0.49.This separator can also facilitate desolvation process,improve exchange current density,restrict two-dimensional Zn^(2+)ion diffusion,and enhance electrochemical kinetics,contributing to significantly inhibited dendrite growth,by-product formation,and hydrogen evolution.Consequently,stable and reversible Zn stripping/plating process is enabled for over 2500 h at 2 mA cm^(-2)and 2 mAh cm^(-2).And great rate capability and excellent cyclability can be achieved for full batteries even under harsh conditions.This work provides new insights into separator design for Zn-based batteries.展开更多
The growth of dendrites and the side reactions occurring at the Zn anode pose significant challenges to the commercialization of aqueous Zn-ion batteries(AZIBs). These challenges arise from the inherent conflict betwe...The growth of dendrites and the side reactions occurring at the Zn anode pose significant challenges to the commercialization of aqueous Zn-ion batteries(AZIBs). These challenges arise from the inherent conflict between mass transfer and electrochemical kinetics. In this study, we propose the use of a multifunctional electrolyte additive based on the xylose(Xylo) molecule to address these issues by modulating the solvation structure and electrode/electrolyte interface, thereby stabilizing the Zn anode. The introduction of the additive alters the solvation structure, creating steric hindrance that impedes charge transfer and then reduces electrochemical kinetics. Furthermore, in-situ analyses demonstrate that the reconstructed electrode/electrolyte interface facilitates stable and rapid Zn^(2+)ion migration and suppresses corrosion and hydrogen evolution reactions. As a result, symmetric cells incorporating the Xylo additive exhibit significantly enhanced reversibility during the Zn plating/stripping process, with an impressively long lifespan of up to 1986 h, compared to cells using pure ZnSO4electrolyte. When combined with a polyaniline cathode, the full cells demonstrate improved capacity and long-term cyclic stability. This work offers an effective direction for improving the stability of Zn anode via electrolyte design, as well as highperformance AZIBs.展开更多
Aqueous Zn-ion batteries (AZIBs) have received considerable attention owing to their various advantages such as safety,low cost,simple battery assembly conditions,and high ionic conductivity.However,they still suffer ...Aqueous Zn-ion batteries (AZIBs) have received considerable attention owing to their various advantages such as safety,low cost,simple battery assembly conditions,and high ionic conductivity.However,they still suffer from serious problems,including uncontrollable dendrite growth,corrosion,hydrogen evolution reaction (HER) from water decomposition,electrode passivation,and unexpected by-products.The creation of a uniform artificial nanocrystal layer on the Zn anode surface is a promising strategy for resolving these issues.Herein,we propose the use of a perovskite CaTiO_(3)(CTO) protective layer on Zn(CTO@Zn) as a promising approach for improving the performance of AZIBs.The CTO artificial layer provides an efficient pathway for Zn ion diffusion towards the Zn metal because of the high dielectric constant (εr=180) and ferroelectric characteristics that enable the alignment of dipole moments and redistribute the Zn^(2+)ions in the CTO layer.By avoiding the direct contact of the Zn anode with the electrolyte solution,the uneven dendrite growth,corrosion,parasitic side reactions,and HER are mitigated,while CTO retains its mechanical and chemical robustness during cycling.Consequently,CTO@Zn demonstrates an improved lifespan in a symmetric cell configuration compared with bare Zn.CTO@Zn shows steady overpotential (~68 m V) for 1500 h at 1 mA cm^(-2)/0.5 mA h cm^(-2),excelling bare Zn.Moreover,when paired with the V_(2)O_(5)-C cathode,the CTO@Zn//V_(2)O_(5)-C full battery delivers 148.4 mA h g^(-1)(based on the mass of the cathode) after 300 cycles.This study provides new insights into Zn metal anodes and the development of high-performance AZIBs.展开更多
Aqueous Ni-Zn microbatteries are safe,reliable and inexpensive but notoriously suffer from inadequate energy and power densities.Herein,we present a novel mechanism of superoxide-activated Ni substrate that realizes t...Aqueous Ni-Zn microbatteries are safe,reliable and inexpensive but notoriously suffer from inadequate energy and power densities.Herein,we present a novel mechanism of superoxide-activated Ni substrate that realizes the redox reaction featuring three-electron transfers(Ni↔Ni3+).The superoxide activates the direct redox reaction between Ni substrate and KNiO_(2)by lowering the reaction Gibbs free energy,supported by in-situ Raman and density functional theory simulations.The prepared chronopotentiostatic superoxidation-activated Ni(CPS-Ni)electrodes exhibit an ultrahigh capacity of 3.21 mAh cm^(-2)at the current density of 5 mA cm^(-2),nearly 8 times that of traditional one-electron processes electrodes.Even under the ultrahigh 200 mA cm^(-2)current density,the CPS-Ni electrodes show 86.4%capacity retention with a Columbic efficiency of 99.2%after 10,000 cycles.The CPS-Ni||Zn microbattery achieves an exceptional energy density of 6.88 mWh cm^(-2)and power density of 339.56 mW cm^(-2).Device demonstration shows that the power source can continuously operate for more than 7 days in powering the sensing and computation intensive practical application of photoplethysmographic waveform monitoring.This work paves the way to the development of multi-electron transfer mechanisms for advanced aqueous Ni-Zn batteries with high capacity and long lifetime.展开更多
Rechargeable aqueous zinc-ion batteries(AZIBs)exhibit appreciable potential in the domain of electrochemical energy storage.However,there are serious challenges for AZIBs,for instance zinc dendrite growth,hydrogen evo...Rechargeable aqueous zinc-ion batteries(AZIBs)exhibit appreciable potential in the domain of electrochemical energy storage.However,there are serious challenges for AZIBs,for instance zinc dendrite growth,hydrogen evolution reaction(HER),and corrosion side reactions.Herein,we propose a surface engineering modification strategy for coating the montmorillonite(MMT)layer onto the surface of the Zn anode to tackle these issues,thereby achieving high cycling stability for rechargeable AZIBs.The results reveal that the MMT layer on the surface of the Zn anode is able to provide ordered zincophilic channels for zinc ions migration,facilitating the reaction kinetics of zinc ions.Density functional theory(DFT)calculations and water contact angle(CA)tests prove that MMT@Zn anode exhibits superior adsorption capacity for Zn^(2+)and better hydrophobicity than the bare Zn anode,thereby achieving excellent cycling stability.Moreover,the MMT@Zn||MMT@Zn symmetric cell holds the stable cycling over 5600 h at 0.5 mA cm^(-2)and 0.125 m A h cm^(-2),even exceeding 1800 h long cycling under harsh conditions of 5 m A cm^(-2)and 1.25 m A h cm^(-2).The MMT@Zn||V_(2)O_(5)full cell reaches over 3000 cycles at 2 A g^(-1)with excellent rate capability.Therefore,this surface engineering modification strategy for enhancing the electrochemical performance of AZIBs represents a promising application.展开更多
Aqueous zincion batteries are highly favored for grid-level energy storage owing to their low cost and high safety,but their practical application is limited by slow ion migration.To address this,a strategy has been d...Aqueous zincion batteries are highly favored for grid-level energy storage owing to their low cost and high safety,but their practical application is limited by slow ion migration.To address this,a strategy has been developed to create a cation-accelerating electric field on the surface of the cathode to achieve ultrafast Zn^(2+)diffusion kinetics.By employing electrodeposition to coat MoS_(2)on the surface of BaV_(6)O_(16)·3H_(2)O nanowires,the directional builtin electric field generated at the heterointerface acts as a cation accelerator,continuously accelerating Zn^(2+)diffusion into the active material.The optimized Zn^(2+)diffusion coefficient in CC@BaV-V_(6)O_(16)·3H_(2)@MoS_(2)(7.5×10^(8)cm^(2)s^(-1)) surpasses that of most reported V-based cathodes.Simultaneously,MoS_(2)serving as a cathodic armor extends the cycling life of the Zn-CC@BaV_(6)O_(16)·3H_(2)@MoS_(2)full batteries to over 10000 cycles.This work provides valuable insights into optimizing ion diffusion kinetics for high-performance energy storage devices.展开更多
The gas-droplet two-phase reacting flow in a model combustor with the V-gutter flame holder is studied by an Eulerian-Lagrangian large-eddy simulation (LES) approach. The k-equation subgrid-scale model is used to simu...The gas-droplet two-phase reacting flow in a model combustor with the V-gutter flame holder is studied by an Eulerian-Lagrangian large-eddy simulation (LES) approach. The k-equation subgrid-scale model is used to simulate the subgrid eddy viscosity, and the eddy-break-up (EBU) combustion subgrid-scale model is used to determine the chemical reaction rate. A two-step turbulent combustion subgrid-scale model is employed for calculating carbon monoxide CO concentration, and the NO subgrid-scale pollutant formation model for the evaluation of the rate of NO formation. The heat flux model is applied to the prediction of radiant heat transfer. The gas phase is solved with the SIMPLE algorithm and a hybrid scheme in the staggered grid system. The liquid phase equations are solved in a Lagrangian frame in reference of the particle-source-in-cell (PSIC) algorithm. From simulation results, the exchange of mass, moment and energy between gas and particle fields for the reacting flow in the afterburner with a V-gutter flame holder can be obtained. By the comparison of experimental and simulation results, profile temperature and pollutant of the outlet are quite in agreement with experimental data. Results show that the LES approach for predicting the two-phase instantaneous reacting flow and pollutant emissions in the afterburner is feasible.展开更多
Oil-water two-phase flow is ubiquitous in shale strata due to the existence of connate water and the injection of fracturing fluid.In this work,we propose a relative permeability model based on a modified Hagen-Poiseu...Oil-water two-phase flow is ubiquitous in shale strata due to the existence of connate water and the injection of fracturing fluid.In this work,we propose a relative permeability model based on a modified Hagen-Poiseuille(HP)equation and shale reconstruction algorithm.The proposed model can consider the nanoconfined effects(slip length and spatially varying viscosity),oil-water distribution,pore size distribution(PSD),total organic matter content(TOC),and micro-fracture.The results show that the increasing contact angles of organic matters(OM)and inorganic minerals(iOM)increase the relative permeability of both oil and water.As the viscosity ratio increases,the relative permeability of oil phase increases while that of water phase decreases,due to the different water-oil distribution.The effective permeability of both oil and water decreases with the increasing TOC.However,the relative permeability of water phase increases while that of oil phase decreases.The increasing number and decreasing deviation angle of micro-fracture increase the effective permeability of oil and water.However,microfracture has a minor effect on relative permeability.Our model can help understand oil-water twophase flow in shale reservoirs and provide parameter characterization for reservoir numerical simulation.展开更多
The existence of water phase occupies oil flow area and impacts the confined oil flow behavior at the solid substrate in inorganic nanopores of shale oil reservoirs,resulting in a completely different flow pattern whe...The existence of water phase occupies oil flow area and impacts the confined oil flow behavior at the solid substrate in inorganic nanopores of shale oil reservoirs,resulting in a completely different flow pattern when compared with the single oil phase flow.This study proposes an analytical model to describe the water-oil two-phase flow.In this model,water slippage at the solid substrate is considered while oil slip is introduced to calculate the oil movement at the solid-oil boundary in dry conditions.It is proven that the oil flow profiles of both the two-phase model and single-phase model show parabolic shapes,but the oil flow capacity drops when water takes up the flow space and the impact of water is more significant when the pore dimension is smaller than 30 nm.Also,the oil flow velocity at a pore center is found to drop linearly given a larger water saturation in wet conditions.The effects of surface wettability and oil properties on water-oil flow are also discussed.Compared with the existing singlephase models,this model describes oil flow pattern in the wet condition with the incorporation of the influence of nanopore properties,which better predicts the oil transport in actual reservoir conditions.Water-oil relative permeability curves are also obtained to improve oil yield.展开更多
Applying the standard Galerkin finite element method for solving flow problems in porous media encounters some difficulties such as numerical oscillation at the shock front and discontinuity of the velocity field on e...Applying the standard Galerkin finite element method for solving flow problems in porous media encounters some difficulties such as numerical oscillation at the shock front and discontinuity of the velocity field on element faces.Discontinuity of velocity field leads this method not to conserve mass locally.Moreover,the accuracy and stability of a solution is highly affected by a non-conservative method.In this paper,a three dimensional control volume finite element method is developed for twophase fluid flow simulation which overcomes the deficiency of the standard finite element method,and attains high-orders of accuracy at a reasonable computational cost.Moreover,this method is capable of handling heterogeneity in a very rational way.A fully implicit scheme is applied to temporal discretization of the governing equations to achieve an unconditionally stable solution.The accuracy and efficiency of the method are verified by simulating some waterflooding experiments.Some representative examples are presented to illustrate the capability of the method to simulate two-phase fluid flow in heterogeneous porous media.展开更多
Electromagnetic Computer Tomography （ECT） is a method to probe the interior of an inhomogeneous medium via surface measurement in a non-linear way. Due to the great differences in conductivity and permittivity betwe...Electromagnetic Computer Tomography （ECT） is a method to probe the interior of an inhomogeneous medium via surface measurement in a non-linear way. Due to the great differences in conductivity and permittivity between oil and water in the well, Electromagnetic Tomography Well Logging （ETWL）, a new flow imaging measurement system, is proposed to describe the distribution and movement of oil/water two-phase flow in the well by scanning the detected region and applying a suitable data processing algorithm. The results of the numerical simulation and physical modeling show that the system could provide a clear image of the flow profile.展开更多
基金The authors gratefully acknowledge financial support from National Key Research and Development Program of China(Nos.2021YFC2101200 and 2021YFB3802200)National Natural Science Foundation of China(Nos.22178251,21878216,91934302,21838008 and 21878215)+1 种基金Program of Introducing Talents of Discipline to Universities(No.BP0618007)the Haihe Laboratory of Sustainable Chemical Transformations.
文摘Aqueous two-phase system features with ultralow interfacial tension and thick interfacial region,affording unique confined space for membrane assembly.Here,for the first time,an aqueous two-phase interfacial assembly method is proposed to fabricate covalent organic framework(COF)membranes.The aqueous solution containing polyethylene glycol and dextran undergoes segregated phase separation into two water-rich phases.By respectively distributing aldehyde and amine monomers into two aqueous phases,a series of COF membranes are fabricated at water-water interface.The resultant membranes exhibit high NaCl rejection of 93.0-93.6% and water permeance reaching 1.7-3.7 L m^(−2) h^(−1) bar^(−1),superior to most water desalination membranes.Interestingly,the interfacial tension is found to have pronounced effect on membrane structures.The appropriate interfacial tension range(0.1-1.0 mN m^(−1))leads to the tight and intact COF membranes.Furthermore,the method is extended to the fabrication of other COF and metal-organic polymer membranes.This work is the first exploitation of fabricating membranes in all-aqueous system,confering a green and generic method for advanced membrane manufacturing.
基金the financial support from the National Natural Science Foundation of China (No.42102127)the Postdoctoral Research Foundation of China (No.2024 M751860)。
文摘Cleat serves as the primary flow pathway for coalbed methane(CBM)and water.However,few studies consider the impact of local contact on two-phase flow within cleats.A visual generalized model of endogenous cleats was constructed based on microfluidics.A microscopic and mesoscopic observation technique was proposed to simultaneously capture gas-liquid interface morphology of pores and throat and the two-phase flow characteristics in entire cleat system.The local contact characteristics of cleats reduced absolute permeability,which resulted in a sharp increase in the starting pressure.The reduced gas flow capacity narrowed the co-infiltration area and decreased water saturation at the isotonic point in a hydrophilic environment.The increased local contact area of cleats weakened gas phase flow capacity and narrowed the co-infiltration area.Jumping events occurred in methane-water flow due to altered porosity caused by local contact in cleats.The distribution of residual phases changed the jumping direction on the micro-scale as well as the dominant channel on the mesoscale.Besides,jumping events caused additional energy dissipation,which was ignored in traditional two-phase flow models.This might contribute to the overestimation of relative permeability.The work provides new methods and insights for investigating unsaturated flow in complex porous media.
基金the support of the Opening Fund of State Key Laboratory of Multiphase Flow in Power Engineering(SKLMF-KF-2102)。
文摘Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to pipeline-riser flow needs evaluation since the flow condition in pipeline-riser is quite different from the original data where they were derived from. In the present study, a comprehensive evaluation of 24prevailing correlation in predicting frictional pressure drop is carried out based on experimentally measured data of air-water and air-oil two-phase flows in pipeline-riser. Experiments are performed in a system having different configuration of pipeline-riser with the inclination of the downcomer varied from-2°to-5°to investigated the effect of the elbow on the frictional pressure drop in the riser. The inlet gas velocity ranges from 0.03 to 6.2 m/s, and liquid velocity varies from 0.02 to 1.3 m/s. A total of885 experimental data points including 782 on air-water flows and 103 on air-oil flows are obtained and used to access the prediction ability of the correlations. Comparison of the predicted results with the measured data indicate that a majority of the investigated correlations under-predict the pressure drop on severe slugging. The result of this study highlights the requirement of new method considering the effect of pipe layout on the frictional pressure drop.
基金supported by the National Natural Science Foundation of China Joint Fund Project (Grant/Award Number: U20B6003)National Natural Science Foundation of China (Grant/Award Number: 52304054)。
文摘Understanding fingering, as a challenge to stable displacement during the immiscible flow, has become a crucial phenomenon for geological carbon sequestration, enhanced oil recovery, and groundwater protection. Typically governed by gravity, viscous and capillary forces, these factors lead invasive fluids to occupy pore space irregularly and incompletely. Previous studies have demonstrated capillary numbers,describing the viscous and capillary forces, to quantificationally induce evolution of invasion patterns.While the evolution mechanisms of invasive patterns have not been deeply elucidated under the constant capillary number and three variable parameters including velocity, viscosity, and interfacial tension.Our research employs two horizontal visualization systems and a two-phase laminar flow simulation to investigate the tendency of invasive pattern transition by various parameters at the pore scale. We showed that increasing invasive viscosity or reducing interfacial tension in a homogeneous pore space significantly enhanced sweep efficiency, under constant capillary number. Additionally, in the fingering crossover pattern, the region near the inlet was prone to capillary fingering with multi-directional invasion, while the viscous fingering with unidirectional invasion was more susceptible occurred in the region near the outlet. Furthermore, increasing invasive viscosity or decreasing invasive velocity and interfacial tension promoted the extension of viscous fingering from the outlet to the inlet, presenting that the subsequent invasive fluid flows toward the outlet. In the case of invasive trunk along a unidirectional path, the invasive flow increased exponentially closer to the outlet, resulting in a significant decrease in the width of the invasive interface. Our work holds promising applications for optimizing invasive patterns in heterogeneous porous media.
基金This work is supported by the National Natural Science Foundation of China(No.52104049)the Young Elite Scientist Sponsorship Program by Beijing Association for Science and Technology(No.BYESS2023262)Science Foundation of China University of Petroleum,Beijing(No.2462022BJRC004).
文摘Polymer flooding in fractured wells has been extensively applied in oilfields to enhance oil recovery.In contrast to water,polymer solution exhibits non-Newtonian and nonlinear behavior such as effects of shear thinning and shear thickening,polymer convection,diffusion,adsorption retention,inaccessible pore volume and reduced effective permeability.Meanwhile,the flux density and fracture conductivity along the hydraulic fracture are generally non-uniform due to the effects of pressure distribution,formation damage,and proppant breakage.In this paper,we present an oil-water two-phase flow model that captures these complex non-Newtonian and nonlinear behavior,and non-uniform fracture characteristics in fractured polymer flooding.The hydraulic fracture is firstly divided into two parts:high-conductivity fracture near the wellbore and low-conductivity fracture in the far-wellbore section.A hybrid grid system,including perpendicular bisection(PEBI)and Cartesian grid,is applied to discrete the partial differential flow equations,and the local grid refinement method is applied in the near-wellbore region to accurately calculate the pressure distribution and shear rate of polymer solution.The combination of polymer behavior characterizations and numerical flow simulations are applied,resulting in the calculation for the distribution of water saturation,polymer concentration and reservoir pressure.Compared with the polymer flooding well with uniform fracture conductivity,this non-uniform fracture conductivity model exhibits the larger pressure difference,and the shorter bilinear flow period due to the decrease of fracture flow ability in the far-wellbore section.The field case of the fall-off test demonstrates that the proposed method characterizes fracture characteristics more accurately,and yields fracture half-lengths that better match engineering reality,enabling a quantitative segmented characterization of the near-wellbore section with high fracture conductivity and the far-wellbore section with low fracture conductivity.The novelty of this paper is the analysis of pressure performances caused by the fracture dynamics and polymer rheology,as well as an analysis method that derives formation and fracture parameters based on the pressure and its derivative curves.
基金Supported by the National Natural Science Foundation of China(52374043)Key Program of the National Natural Science Foundation of China(52234003).
文摘Based on the displacement discontinuity method and the discrete fracture unified pipe network model,a sequential iterative numerical method was used to build a fracturing-production integrated numerical model of shale gas well considering the two-phase flow of gas and water.The model accounts for the influence of natural fractures and matrix properties on the fracturing process and directly applies post-fracturing formation pressure and water saturation distribution to subsequent well shut-in and production simulation,allowing for a more accurate fracturing-production integrated simulation.The results show that the reservoir physical properties have great impacts on fracture propagation,and the reasonable prediction of formation pressure and reservoir fluid distribution after the fracturing is critical to accurately predict the gas and fluid production of the shale gas wells.Compared with the conventional method,the proposed model can more accurately simulate the water and gas production by considering the impact of fracturing on both matrix pressure and water saturation.The established model is applied to the integrated fracturing-production simulation of practical horizontal shale gas wells.The simulation results are in good agreement with the practical production data,thus verifying the accuracy of the model.
基金supported by the National Natural Science Foundation of China(Grant Nos.22275092,52102107 and 52372084)the Fundamental Research Funds for the Central Universities(Grant No.30923010920)。
文摘Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics devices.In this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) RMFs.In order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this model.It is found that the exothermal reaction in RMFs improved the ignition performance of SCB.In the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low temperature.In addition,it made up for pressure loss in the gas phase.During the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise continuously.This result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.
基金support from the National Natural Science Foundation of China(22209089,22178187)Natural Science Foundation of Shandong Province(ZR2022QB048,ZR2021MB006)+2 种基金Excellent Youth Science Foundation of Shandong Province(Overseas)(2023HWYQ-089)the Taishan Scholars Program of Shandong Province(tsqn201909091)Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University.
文摘Aqueous zinc-halogen batteries are promising candidates for large-scale energy storage due to their abundant resources,intrinsic safety,and high theoretical capacity.Nevertheless,the uncontrollable zinc dendrite growth and spontaneous shuttle effect of active species have prohibited their practical implementation.Herein,a double-layered protective film based on zinc-ethylenediamine tetramethylene phosphonic acid(ZEA)artificial film and ZnF2-rich solid electrolyte interphase(SEI)layer has been successfully fabricated on the zinc metal anode via electrode/electrolyte synergistic optimization.The ZEA-based artificial film shows strong affinity for the ZnF2-rich SEI layer,therefore effectively suppressing the SEI breakage and facilitating the construction of double-layered protective film on the zinc metal anode.Such double-layered architecture not only modulates Zn2+flux and suppresses the zinc dendrite growth,but also blocks the direct contact between the metal anode and electrolyte,thus mitigating the corrosion from the active species.When employing optimized metal anodes and electrolytes,the as-developed zinc-(dual)halogen batteries present high areal capacity and satisfactory cycling stability.This work provides a new avenue for developing aqueous zinc-(dual)halogen batteries.
基金financially supported by the National Natural Science Foundation of China(Grant No.52171147)the Tenthousand Talents Program+2 种基金the K.C.Wong Pioneer Talent Programthe National Key R&D Program of China(2024YFE0101100)the Inner Mengolia Science and Technology Plan(No.2021ZD0033).
文摘Aqueous Zn-ion batteries have attracted much attention due to their unique high safety and low-cost merits.However,their practical applications are at a slow pace due to their short cycle life,which fundamentally results from the instability of the positive/negative electrode interface in the traditional dilute aqueous electrolytes with high water activity.Developing highly concentrated electrolyte(HCE)has been considered as an effective solution.Unlike previous studies of single salt-based HCE(SSHCE),herein,a new dual-salt HCE(15 m ZnCl_(2)+10 m NH_(4)NH_(2)SO_(3)DS-HCE)was proposed for the first time.DS-HCE was proven to simultaneously possess higher conductivity than traditional dilute electrolytes and ultralow water activity of SS-HCE by the regulation of dual high-concentration salts on the solvation structure,which renders the Zn‖Zn symmetric cell the record-long cycling life of 2200 h compared with those with SS-HCE(30 m ZnCl_(2),300 h)and other reported HCEs.Additionally,the Zn‖NH_(4)V_(4)O_(10)full cell with DS-HCE demonstrated impressed rate capability within a wide-range current densities from 0.1 to 10 A g^(-1).Moreover,at the high current density of 5 A g^(-1),the full cell shows almost100%capacity retention after 4000 cycles,which indicates the promising future of the DS-HCE system for long-duration aqueous Zn-ion batteries.
基金the financial support from the Natural Science Foundation of Jiangsu Province(BK20231292)the Jiangsu Agricultural Science and Technology Innovation Fund(CX(24)3091)+2 种基金the National Natural Science Foundation of China(12464032)the Natural Science Foundation of Jiangxi Province(20232BAB201032)supported by the high performance computing university-level public platform of Jinggangshan University.
文摘Aqueous zinc-ion batteries encounter enormous challenges such as Zn dendrites and parasitic reactions.Separator modification is a highly effective strategy to address these issues.With the advantages of low cost,nontoxicity,biodegradability,good film-forming ability,superior hydro phi licity,and rich functional groups,chitosan is an ideal matrix for constructing separators.However,the presence of positive charges within chitosan in weakly acidic electrolytes is unfavorable for dendrite inhibition.Herein,Schiff base reaction is introduced to modify chitosan matrix,transforming its charge polarity from positive to negative.Additionally,NbN with excellent zincophilicity is coated onto chitosan matrix,forming a Janus separator with low thickness of 19μm and considerably improved mechanical properties.The resultant separator can promote the transport of Zn^(2+)ions while triggering a repulsive shielding effect against anions,therefore dramatically enhancing Zn^(2+)ion transfer number from 0.28 to 0.49.This separator can also facilitate desolvation process,improve exchange current density,restrict two-dimensional Zn^(2+)ion diffusion,and enhance electrochemical kinetics,contributing to significantly inhibited dendrite growth,by-product formation,and hydrogen evolution.Consequently,stable and reversible Zn stripping/plating process is enabled for over 2500 h at 2 mA cm^(-2)and 2 mAh cm^(-2).And great rate capability and excellent cyclability can be achieved for full batteries even under harsh conditions.This work provides new insights into separator design for Zn-based batteries.
文摘The growth of dendrites and the side reactions occurring at the Zn anode pose significant challenges to the commercialization of aqueous Zn-ion batteries(AZIBs). These challenges arise from the inherent conflict between mass transfer and electrochemical kinetics. In this study, we propose the use of a multifunctional electrolyte additive based on the xylose(Xylo) molecule to address these issues by modulating the solvation structure and electrode/electrolyte interface, thereby stabilizing the Zn anode. The introduction of the additive alters the solvation structure, creating steric hindrance that impedes charge transfer and then reduces electrochemical kinetics. Furthermore, in-situ analyses demonstrate that the reconstructed electrode/electrolyte interface facilitates stable and rapid Zn^(2+)ion migration and suppresses corrosion and hydrogen evolution reactions. As a result, symmetric cells incorporating the Xylo additive exhibit significantly enhanced reversibility during the Zn plating/stripping process, with an impressively long lifespan of up to 1986 h, compared to cells using pure ZnSO4electrolyte. When combined with a polyaniline cathode, the full cells demonstrate improved capacity and long-term cyclic stability. This work offers an effective direction for improving the stability of Zn anode via electrolyte design, as well as highperformance AZIBs.
基金Basic Science Research Capacity Enhancement Project through the Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (2019R1A6C1010016)Basic Science Research Program through the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education (NRF-2021R1F1A1050130)。
文摘Aqueous Zn-ion batteries (AZIBs) have received considerable attention owing to their various advantages such as safety,low cost,simple battery assembly conditions,and high ionic conductivity.However,they still suffer from serious problems,including uncontrollable dendrite growth,corrosion,hydrogen evolution reaction (HER) from water decomposition,electrode passivation,and unexpected by-products.The creation of a uniform artificial nanocrystal layer on the Zn anode surface is a promising strategy for resolving these issues.Herein,we propose the use of a perovskite CaTiO_(3)(CTO) protective layer on Zn(CTO@Zn) as a promising approach for improving the performance of AZIBs.The CTO artificial layer provides an efficient pathway for Zn ion diffusion towards the Zn metal because of the high dielectric constant (εr=180) and ferroelectric characteristics that enable the alignment of dipole moments and redistribute the Zn^(2+)ions in the CTO layer.By avoiding the direct contact of the Zn anode with the electrolyte solution,the uneven dendrite growth,corrosion,parasitic side reactions,and HER are mitigated,while CTO retains its mechanical and chemical robustness during cycling.Consequently,CTO@Zn demonstrates an improved lifespan in a symmetric cell configuration compared with bare Zn.CTO@Zn shows steady overpotential (~68 m V) for 1500 h at 1 mA cm^(-2)/0.5 mA h cm^(-2),excelling bare Zn.Moreover,when paired with the V_(2)O_(5)-C cathode,the CTO@Zn//V_(2)O_(5)-C full battery delivers 148.4 mA h g^(-1)(based on the mass of the cathode) after 300 cycles.This study provides new insights into Zn metal anodes and the development of high-performance AZIBs.
基金supported by InnoHK Project at Hong Kong Centre for Cerebro-cardiovascular Health Engineering (COCHE)City University of Hong Kong (7006108)。
文摘Aqueous Ni-Zn microbatteries are safe,reliable and inexpensive but notoriously suffer from inadequate energy and power densities.Herein,we present a novel mechanism of superoxide-activated Ni substrate that realizes the redox reaction featuring three-electron transfers(Ni↔Ni3+).The superoxide activates the direct redox reaction between Ni substrate and KNiO_(2)by lowering the reaction Gibbs free energy,supported by in-situ Raman and density functional theory simulations.The prepared chronopotentiostatic superoxidation-activated Ni(CPS-Ni)electrodes exhibit an ultrahigh capacity of 3.21 mAh cm^(-2)at the current density of 5 mA cm^(-2),nearly 8 times that of traditional one-electron processes electrodes.Even under the ultrahigh 200 mA cm^(-2)current density,the CPS-Ni electrodes show 86.4%capacity retention with a Columbic efficiency of 99.2%after 10,000 cycles.The CPS-Ni||Zn microbattery achieves an exceptional energy density of 6.88 mWh cm^(-2)and power density of 339.56 mW cm^(-2).Device demonstration shows that the power source can continuously operate for more than 7 days in powering the sensing and computation intensive practical application of photoplethysmographic waveform monitoring.This work paves the way to the development of multi-electron transfer mechanisms for advanced aqueous Ni-Zn batteries with high capacity and long lifetime.
基金National Natural Science Foundation of China(Grant No.22005318,22379152)Western Young Scholars Foundations of Chinese Academy of Sciences+4 种基金Lanzhou Youth Science and Technology Talent Innovation Project(Grant No.2023-NQ-86,No.2023-QN-96)Lanzhou Chengguan District Science and Technology Plan Project(Grant No.2023-rc-4,2022-rc-4)Collaborative Innovation Alliance Fund for Young Science and Technology Worker(Grant No.HZJJ23-7)National Nature Science Foundations of Gansu Province(Grant No.21JR11RA020)Fundamental Research Funds for the Central Universities(Grant No.31920220073,31920230128)。
文摘Rechargeable aqueous zinc-ion batteries(AZIBs)exhibit appreciable potential in the domain of electrochemical energy storage.However,there are serious challenges for AZIBs,for instance zinc dendrite growth,hydrogen evolution reaction(HER),and corrosion side reactions.Herein,we propose a surface engineering modification strategy for coating the montmorillonite(MMT)layer onto the surface of the Zn anode to tackle these issues,thereby achieving high cycling stability for rechargeable AZIBs.The results reveal that the MMT layer on the surface of the Zn anode is able to provide ordered zincophilic channels for zinc ions migration,facilitating the reaction kinetics of zinc ions.Density functional theory(DFT)calculations and water contact angle(CA)tests prove that MMT@Zn anode exhibits superior adsorption capacity for Zn^(2+)and better hydrophobicity than the bare Zn anode,thereby achieving excellent cycling stability.Moreover,the MMT@Zn||MMT@Zn symmetric cell holds the stable cycling over 5600 h at 0.5 mA cm^(-2)and 0.125 m A h cm^(-2),even exceeding 1800 h long cycling under harsh conditions of 5 m A cm^(-2)and 1.25 m A h cm^(-2).The MMT@Zn||V_(2)O_(5)full cell reaches over 3000 cycles at 2 A g^(-1)with excellent rate capability.Therefore,this surface engineering modification strategy for enhancing the electrochemical performance of AZIBs represents a promising application.
基金National Natural Science Foundation of China (61761047 and 41876055)Program for Innovative Research Team (in Science and Technology) in University of Yunnan Province。
文摘Aqueous zincion batteries are highly favored for grid-level energy storage owing to their low cost and high safety,but their practical application is limited by slow ion migration.To address this,a strategy has been developed to create a cation-accelerating electric field on the surface of the cathode to achieve ultrafast Zn^(2+)diffusion kinetics.By employing electrodeposition to coat MoS_(2)on the surface of BaV_(6)O_(16)·3H_(2)O nanowires,the directional builtin electric field generated at the heterointerface acts as a cation accelerator,continuously accelerating Zn^(2+)diffusion into the active material.The optimized Zn^(2+)diffusion coefficient in CC@BaV-V_(6)O_(16)·3H_(2)@MoS_(2)(7.5×10^(8)cm^(2)s^(-1)) surpasses that of most reported V-based cathodes.Simultaneously,MoS_(2)serving as a cathodic armor extends the cycling life of the Zn-CC@BaV_(6)O_(16)·3H_(2)@MoS_(2)full batteries to over 10000 cycles.This work provides valuable insights into optimizing ion diffusion kinetics for high-performance energy storage devices.
文摘The gas-droplet two-phase reacting flow in a model combustor with the V-gutter flame holder is studied by an Eulerian-Lagrangian large-eddy simulation (LES) approach. The k-equation subgrid-scale model is used to simulate the subgrid eddy viscosity, and the eddy-break-up (EBU) combustion subgrid-scale model is used to determine the chemical reaction rate. A two-step turbulent combustion subgrid-scale model is employed for calculating carbon monoxide CO concentration, and the NO subgrid-scale pollutant formation model for the evaluation of the rate of NO formation. The heat flux model is applied to the prediction of radiant heat transfer. The gas phase is solved with the SIMPLE algorithm and a hybrid scheme in the staggered grid system. The liquid phase equations are solved in a Lagrangian frame in reference of the particle-source-in-cell (PSIC) algorithm. From simulation results, the exchange of mass, moment and energy between gas and particle fields for the reacting flow in the afterburner with a V-gutter flame holder can be obtained. By the comparison of experimental and simulation results, profile temperature and pollutant of the outlet are quite in agreement with experimental data. Results show that the LES approach for predicting the two-phase instantaneous reacting flow and pollutant emissions in the afterburner is feasible.
基金supported by the National Natural Science Foundation of China(51804328,51974348)
文摘Oil-water two-phase flow is ubiquitous in shale strata due to the existence of connate water and the injection of fracturing fluid.In this work,we propose a relative permeability model based on a modified Hagen-Poiseuille(HP)equation and shale reconstruction algorithm.The proposed model can consider the nanoconfined effects(slip length and spatially varying viscosity),oil-water distribution,pore size distribution(PSD),total organic matter content(TOC),and micro-fracture.The results show that the increasing contact angles of organic matters(OM)and inorganic minerals(iOM)increase the relative permeability of both oil and water.As the viscosity ratio increases,the relative permeability of oil phase increases while that of water phase decreases,due to the different water-oil distribution.The effective permeability of both oil and water decreases with the increasing TOC.However,the relative permeability of water phase increases while that of oil phase decreases.The increasing number and decreasing deviation angle of micro-fracture increase the effective permeability of oil and water.However,microfracture has a minor effect on relative permeability.Our model can help understand oil-water twophase flow in shale reservoirs and provide parameter characterization for reservoir numerical simulation.
基金the NSERC/Energi Simulation and Alberta Innovates Chairs for providing research fundingthe Beijing Natural Science Foundation(2204093)Science Foundation of China University of Petroleum,Beijing(No.2462018YJRC033)for providing research funding。
文摘The existence of water phase occupies oil flow area and impacts the confined oil flow behavior at the solid substrate in inorganic nanopores of shale oil reservoirs,resulting in a completely different flow pattern when compared with the single oil phase flow.This study proposes an analytical model to describe the water-oil two-phase flow.In this model,water slippage at the solid substrate is considered while oil slip is introduced to calculate the oil movement at the solid-oil boundary in dry conditions.It is proven that the oil flow profiles of both the two-phase model and single-phase model show parabolic shapes,but the oil flow capacity drops when water takes up the flow space and the impact of water is more significant when the pore dimension is smaller than 30 nm.Also,the oil flow velocity at a pore center is found to drop linearly given a larger water saturation in wet conditions.The effects of surface wettability and oil properties on water-oil flow are also discussed.Compared with the existing singlephase models,this model describes oil flow pattern in the wet condition with the incorporation of the influence of nanopore properties,which better predicts the oil transport in actual reservoir conditions.Water-oil relative permeability curves are also obtained to improve oil yield.
基金Iranian Offshore Oil Company (IOOC) for financial support of this work
文摘Applying the standard Galerkin finite element method for solving flow problems in porous media encounters some difficulties such as numerical oscillation at the shock front and discontinuity of the velocity field on element faces.Discontinuity of velocity field leads this method not to conserve mass locally.Moreover,the accuracy and stability of a solution is highly affected by a non-conservative method.In this paper,a three dimensional control volume finite element method is developed for twophase fluid flow simulation which overcomes the deficiency of the standard finite element method,and attains high-orders of accuracy at a reasonable computational cost.Moreover,this method is capable of handling heterogeneity in a very rational way.A fully implicit scheme is applied to temporal discretization of the governing equations to achieve an unconditionally stable solution.The accuracy and efficiency of the method are verified by simulating some waterflooding experiments.Some representative examples are presented to illustrate the capability of the method to simulate two-phase fluid flow in heterogeneous porous media.
基金This work was supported by the National Natural Science Foundation of China(60472019).
文摘Electromagnetic Computer Tomography （ECT） is a method to probe the interior of an inhomogeneous medium via surface measurement in a non-linear way. Due to the great differences in conductivity and permittivity between oil and water in the well, Electromagnetic Tomography Well Logging （ETWL）, a new flow imaging measurement system, is proposed to describe the distribution and movement of oil/water two-phase flow in the well by scanning the detected region and applying a suitable data processing algorithm. The results of the numerical simulation and physical modeling show that the system could provide a clear image of the flow profile.
