The newly formulated non-Newtonian rivulet flows streaming down an inclined planar surface,with additional periodic perturbations arising from the application of the 2nd Stokes problem to the investigation of rivulet ...The newly formulated non-Newtonian rivulet flows streaming down an inclined planar surface,with additional periodic perturbations arising from the application of the 2nd Stokes problem to the investigation of rivulet dynamics,are demonstrated in the current research.Hereby,the 2nd Stokes problem assumes that the surface,with a thin shared layer of the fluid on it,oscillates in a harmonic manner along the x-axis of the rivulet flow,which coincides with the main flow direction streaming down the underlying surface.We obtain the exact extension of the rivulet flow family,clarifying the structure of the pressure field,which fully absorbs the arising perturbation.The profile of the velocity field is assumed to be Gaussian-type with a non-zero level of plasticity.Hence,the absolutely non-Newtonian case of the viscoplastic flow solution,which satisfies the motion and continuity equations,is considered(with particular cases of exact solutions for pressure).The perturbed governing equations of motion for rivulet flows then result in the Riccati-type ordinary differential equation(ODE),describing the dynamics of the coordinate x(t).The approximated schematic dynamics are presented in graphical plots.展开更多
Photothermal synergistic catalytic systems for treating volatile organic compounds(VOCs)have attracted signif-icant attention due to their energy efficiency and potential to reduce carbon emissions.However,the mechani...Photothermal synergistic catalytic systems for treating volatile organic compounds(VOCs)have attracted signif-icant attention due to their energy efficiency and potential to reduce carbon emissions.However,the mechanism underlying the synergistic reaction remains a critical issue.This study introduces a photothermal synergistic system for the removal of ethyl acetate(EA)by synthesizing Cu-doped OMS-2(denoted as Cu-OMS-2).Under ultraviolet-visible(UV–Vis)irradiation in a flow system,the Cu-OMS-2 catalyst exhibited significantly enhanced performance in the EA degradation process,nearly doubling the effectiveness of pure OMS-2,and increasing carbon dioxide yield by 20%.This exceptional performance is attributed to the synergistic effect of increased oxygen vacancies(OV)at OMS-2 active sites and Cu doping,as confirmed by H2-TPR,O_(2)-TPD,and CO consump-tion measurements.This study clarifies the catalytic mechanism of light-assisted thermocatalysis and offers a novel strategy for designing photothermal catalysts with homogeneous Cu-doped nanorods for VOC removal.展开更多
The coupled chemo-mechanical impact of supercritical CO_(2)-H_(2)O(ScCO_(2)-H_(2)O)reactions on fracture geometry and nonlinear flow regimes in deep shale under confining pressures remains inadequately quantified.This...The coupled chemo-mechanical impact of supercritical CO_(2)-H_(2)O(ScCO_(2)-H_(2)O)reactions on fracture geometry and nonlinear flow regimes in deep shale under confining pressures remains inadequately quantified.This study systematically investigates the effects of ScCO_(2)-H_(2)O-shale interactions on fracture morphology and flow properties under confining pressures from 15 MPa to 40 MPa by integrating XRD(X-ray diffraction),micro-CT,3D surface profilometry,and multistage steady-state flow experiments.The results demonstrate that ScCO_(2)-H_(2)O exposure drives pyrite/feldspar dissolution and localized clay precipitation,resulting in fracture branching and macroscopic aperture regularization.Critically,confining pressure dictates the net hydraulic response:under low confining pressure(15-25 MPa),dissolution dominates,enhancing permeability,flow efficiency(Q/VP),and pre-linear flow behavior(n<1).At high confining pressures(30-40 MPa)mechanical compaction and mineral precipitation amplify flow resistance,shifting the flow regime toward quasi-linear behavior,as inertial effects become negligible compared to dominant viscous forces and increased flow resistance.Confining pressure thus critically mediates the dissolution-precipitation balance during ScCO_(2)-H_(2)O treatment,with an optimal window of 15-25 MPa identified for enhancing conductivity while minimizing clogging risk.These findings provide a quantitative framework for predicting stress-dependent flow evolution in chemically altered shale fractures.展开更多
Vanadium redox flow battery(VRFB),as a potential technology for next-generation energy storage system,is restricted by the slow redox kinetics of vanadium ions.Implementing interface engineering strategies to function...Vanadium redox flow battery(VRFB),as a potential technology for next-generation energy storage system,is restricted by the slow redox kinetics of vanadium ions.Implementing interface engineering strategies to functionalize the surface of MXene can effectively address this challenge.Herein,a Nb_(2)CT_(x)/Nb_(2)O_(5)Schottky heterostructure is constructed to facilitate high-speed charge transfer at the VRFB electrode through controllable in-situ oxidation.The loading amount of Nb_(2)O_(5) nanorods on the surface of Nb_(2)CT_(x) nanosheets was regulated by varying the hydrothermal reaction time.Density functional theory calculations confirm that the Schottky barrier formed between Nb_(2)CT_(x) and Nb_(2)O_(5) leads to the establishment of an internal electric field and reconfigures the electronic structure of surficial active sites.The rich pore structure of Nb_(2)CT_(x)/Nb_(2)O_(5) electrode effectively shortens the diffusion path for vanadium ions,while its excellent hydrophilicity enhances the interaction between vanadium ions and the electrodes.Compared with graphite felt,Nb_(2)CT_(x)/Nb_(2)O_(5)-2@GF cell shows a 20%increase in energy efficiency(EE)at 150 mA cm^(-2) cycling,reaching 75%,while maintaining stable performance for over 800 cycles.This means a significant advancement in the development of high-performance electrodes for VRFBs.This work offers an efficient and scalable strategy for the design of redox flow batteries.展开更多
管道输送CO_(2)作为碳捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)产业链的关键环节之一,在海上CCUS发展中发挥着越来越重要的作用。高压密相CO_(2)管道泄压所造成的管道低温脆性断裂、干冰堵塞等问题,严重影响海...管道输送CO_(2)作为碳捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)产业链的关键环节之一,在海上CCUS发展中发挥着越来越重要的作用。高压密相CO_(2)管道泄压所造成的管道低温脆性断裂、干冰堵塞等问题,严重影响海上平台CO_(2)输送管道的安全运行。针对海上平台间高压密相CO_(2)管道,采用LedaFlow动态模拟软件建立CO_(2)输送管道泄压模型,分析海上冬季和夏季环境条件下管道沿程温度、压力和泄压量的变化趋势,并对比管道不同初始输送压力、初始输量和泄压对管道流体低温的影响情况。结果表明,冬季泄压造成的海底管道低温要比夏季泄压时低,故推荐在夏季进行泄压操作。在冬季最低环境温度条件下,适当减小泄压口径能够有效避免沿程温度、压力的大幅变化而导致的管道低温情况。研究成果可为实际海上高压密相CO_(2)输送管道的泄压操作提供参考。展开更多
Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative...Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative permeability experiments on sandstone from a proposed storage site,comple-mented by in situ X-ray imaging and ex situ analyses using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).Despite our use of a brine that was pre-equilibrated with CO_(2),there was a significant reduction in both CO_(2) relative permeability and absolute permeability during multiphase flow due to chemical reactions.This reduction was driven by decreased pore and throat sizes,diminished connectivity,and increased irregularity of pore and throat shapes,as revealed by in situ pore-scale imaging.Mineral dissolution,primarily of feldspar,albite,and calcite,along with precipitation resulting from feldspar-to-kaolinite transformation and fines migration,were identified as contributing factors through SEM-EDS analysis.This work provides a benchmark for storage in mineralogically complex sandstones,for which the impact of chemical reactions on multiphase flow properties has been measured.展开更多
A radical C−C-coupling reaction of acetonitrile into succinonitrile over hydrophobic TiO_(2) photocatalyst with enhanced catalytic activity was developed.In addition,the usage of a flow reactor further improved the ph...A radical C−C-coupling reaction of acetonitrile into succinonitrile over hydrophobic TiO_(2) photocatalyst with enhanced catalytic activity was developed.In addition,the usage of a flow reactor further improved the photon utilization efficiency for succinonitrile synthesis at room temperature.The space time yield of succinonitrile reached 55.59μmol/(g·h)over hydrophobic TiO_(2) catalyst,which was much higher than that of pristine TiO_(2)(4.23μmol/(g·h)).Mechanistic studies revealed that the hydrophobic modification of TiO_(2) promoted the separation and transfer of photogenerated carriers,as well as suppressed their recombination.Hydrophobic TiO_(2) also enhanced the adsorption of−CH3 of acetonitrile,thus facilitating the activation of C−H bond and the utilization efficiency of photocarriers.展开更多
The Görtler vortex is a characteristic flow feature observed in the boundary layer on compression ramp in hypersonic flow.In the context of high-enthalpy plasma flows during aerospace re-entry processes,there is ...The Görtler vortex is a characteristic flow feature observed in the boundary layer on compression ramp in hypersonic flow.In the context of high-enthalpy plasma flows during aerospace re-entry processes,there is currently a lack of effective means to visualize the boundary layer.In this study,the Nitric Oxide Planar Laser-Induced Fluorescence(NO-PLIF)technique was employed to visualize the boundary layer of a compression ramp in a 50-MW arc-heated plasma wind tunnel.Görtler-like vortex structures were observed in the boundary layer of the ramp.This is the first time that Görtler vortices have been clearly observed in a high-enthalpy plasma flow.By varying the flow conditions,the Görtler vortices persisted in the boundary layer of the ramp when the total enthalpy of the arc-heated wind tunnel exceeded 12.3 MJ/kg.Several image processing techniques were applied to extract the structure of high-speed Görtler streaks,and the position of the high-speed streaks was found to be non-fixed,whereas the average Görtler wavelength remained at approximately 30 mm at a 10°ramp and showed limited variation with the total enthalpy.Additionally,a sheet-forming optics system with an adjustable angle and height was designed to enable visualization of the Görtler vortices in the boundary layer of the ramp at different angles and heights.The vortices on the low-angle ramp exhibited better stability and shorter wavelengths.Visualization results at different heights confirmed that the Görtler vortex wavelength was approximately twice the boundary layer thickness.This study demonstrates the feasibility and potential of the PLIF technique for the visualization of the boundary layer in plasma flows,especially with regard to Görtler vortices.展开更多
Global investment in ethylene(C_(2)H_(4))production via nonpetroleum pathways is rising,highlighting its growing importance in the energy and environmental sectors.The electroreduction of carbon dioxide(CO_(2))to C_(2...Global investment in ethylene(C_(2)H_(4))production via nonpetroleum pathways is rising,highlighting its growing importance in the energy and environmental sectors.The electroreduction of carbon dioxide(CO_(2))to C_(2)H_(4) inflow cells is emerging as a promising technology with broad practical applications.Direct delivery of gaseous CO_(2) to the cathode catalyst layer overcomes mass transfer limitations,enhancing reaction rates and enabling high current density.This review summarizes recent research progress in the electrocatalytic CO_(2) reduction reaction(eCO_(2)RR)for selective C_(2)H_(4) production inflow cells.It outlines the principles of eCO_(2)RR to C_(2)H_(4) and discusses the influence of copper-based catalyst morphology,crystal facet,oxidation state,surface modification strategy,and synergistic effects on catalytic performance.In addition,it highlights the compositional structure of theflow cell,and the selection and optimization of operating conditions,including gas diffusion electrodes,electrolytes,ion exchange membranes,and alternative anode reaction types beyond the oxygen evolution reaction.Finally,advances in machine learning are presented for accelerating catalyst screening and predicting dynamic changes in catalysts during reduction.This comprehensive review serves as a valuable reference for the development of efficient catalysts and the construction of electrolytic devices for the electrocatalytic reduction of CO_(2) to C_(2)H_(4).展开更多
This study introduces a Transformer-based multimodal fusion framework for simulating multiphase flow and heat transfer in carbon dioxide(CO_(2))–water enhanced geothermal systems(EGS).The model integrates geological ...This study introduces a Transformer-based multimodal fusion framework for simulating multiphase flow and heat transfer in carbon dioxide(CO_(2))–water enhanced geothermal systems(EGS).The model integrates geological parameters,thermal gradients,and control schedules to enable fast and accurate prediction of complex reservoir dynamics.The main contributions are:(i)development of a workflow that couples physics-based reservoir simulation with a Transformer neural network architecture,(ii)design of physics-guided loss functions to enforce conservation of mass and energy,(iii)application of the surrogate model to closed-loop optimization using a differential evolution(DE)algorithm,and(iv)incorporation of economic performance metrics,such as net present value(NPV),into decision support.The proposed framework achieves root mean square error(RMSE)of 3–5%,mean absolute error(MAE)below 4%,and coefficients of determination greater than 0.95 across multiple prediction targets,including production rates,pressure distributions,and temperature fields.When compared with recurrent neural network(RNN)baselines such as gated recurrent units(GRU)and long short-term memory networks(LSTM),as well as a physics-informed reduced-order model,the Transformer-based approach demonstrates superior accuracy and computational efficiency.Optimization experiments further show a 15–20%improvement in NPV,highlighting the framework’s potential for real-time forecasting,optimization,and decision-making in geothermal reservoir engineering.展开更多
CO_2 is now considered as a novel heat transmission fluid to extract geothermal energy. It can be used for both energy exploitation and CO_2 geological sequestration. Here, a 3-D, "two-spot" pattern well mod...CO_2 is now considered as a novel heat transmission fluid to extract geothermal energy. It can be used for both energy exploitation and CO_2 geological sequestration. Here, a 3-D, "two-spot" pattern well model is developed to analyze the mechanism of CO_2-water displacement and heat extraction. To obtain a deeper understanding of CO_2-geothermal system under some more realistic conditions, heterogeneity of reservoir's hydrological properties is taken into account. Due to the fortissimo mobility of CO_2, as long as the existence of highly permeable zone between the two wells, it is more likely to flow through the highly permeable zone to reach the production well, even though the flow path is longer. The preferential flow shortens circulation time and reduces heat-exchange area, probably leading to early thermal breakthrough, which makes the production fluid temperature decrease rapidly. The analyses of flow dynamics of CO_2-water fluid and heat may be useful for future design of a CO_2-based geothermal development system.展开更多
Although extensive research has been conducted on CO_(2)-enhanced coalbed methane(CO_(2)-ECBM)recovery,most prior studies have focused on the impact of gas adsorption-induced swelling on coal permeability under equili...Although extensive research has been conducted on CO_(2)-enhanced coalbed methane(CO_(2)-ECBM)recovery,most prior studies have focused on the impact of gas adsorption-induced swelling on coal permeability under equilibrium conditions.This paper presents a comprehensive thermo-hydro-mechanical-chemical(THMC)model that integrates thermal expansion and heat conduction(T),gas diffusion in the matrix and gas-water two-phase flow in the fractures(H),matrix and fracture deformation due to poroelasticity(M),and non-equilibrium binary gas adsorption-induced matrix swelling(C)during CO_(2)-ECBM recovery.The accuracy of the proposed model was verified through experimental data,and the model was simulated using finite element method(FEM)software.Simulation results indicate that the permeability evolution can be categorized into three stages.Ignoring the impact of water on gas adsorption properties would lead to an overestimation of the influence of adsorption-induced swelling,while disregarding non-equilibrium adsorption underestimates it.An examination of five designed cases identified critical factors influencing permeability.Parametric analysis shows that increases in the injection pressure,the injection temperature,and the initial permeability promote the competitive adsorption-induced swelling between CH_(4)and CO_(2),leading to increased CH_(4)production and CO_(2)storage.Conversely,an increase in initial water saturation reduces available gas flow space,decreasing both CH_(4)production and CO_(2)storage.Higher irreducible water saturation favors early gas recovery,while lower irreducible water saturation is more advantageous for long-term recovery.展开更多
The increase in CO_(2)injectivity and shifting of CO_(2)-absorbing layers in multilayered geological CO_(2)sequestration(GCS)reservoirs in Ordos,China indicate significantpermeability variations in certain layers.To c...The increase in CO_(2)injectivity and shifting of CO_(2)-absorbing layers in multilayered geological CO_(2)sequestration(GCS)reservoirs in Ordos,China indicate significantpermeability variations in certain layers.To capture these system changes,a numerical model incorporating all 21 aquifers and internal aquitards was developed.The monitored pressure was well matched through multiphase and thermalhydraulic-mechanical(THM)coupling numerical simulations by introducing permeability variations.The results revealed that the permeability in the second layer increased on approximately day 13 due to the abrupt pressure buildup and temperature decrease.Even such a low rate of CO_(2)(2.8 kg/s)injected into the low permeability system initiated some fractures and the permeability in the second layer around the wellbore increased by 722 times.The second critical system change occurred on approximately day 386.As demonstrated in the numerical simulation,the substantial injection of cold CO_(2)induced strong thermal stress,leading to rock contraction and the initiation of several cracks.The permeability of the firstlayer around the wellbore unexpectedly increased by 4 orders of magnitude.Since no additional pressure could drive the CO_(2)into the remaining 17 layers,the total storage capability of the multilayered system was reduced.A whole picture of the system variation is fully presented and the underlying mechanisms are analyzed.It is believed that the phenomenon of thermal-hydraulic fracturing observed in this fieldand the simulation procedures will benefitother fluidinjection and production works in various geotechnical settings.展开更多
文摘The newly formulated non-Newtonian rivulet flows streaming down an inclined planar surface,with additional periodic perturbations arising from the application of the 2nd Stokes problem to the investigation of rivulet dynamics,are demonstrated in the current research.Hereby,the 2nd Stokes problem assumes that the surface,with a thin shared layer of the fluid on it,oscillates in a harmonic manner along the x-axis of the rivulet flow,which coincides with the main flow direction streaming down the underlying surface.We obtain the exact extension of the rivulet flow family,clarifying the structure of the pressure field,which fully absorbs the arising perturbation.The profile of the velocity field is assumed to be Gaussian-type with a non-zero level of plasticity.Hence,the absolutely non-Newtonian case of the viscoplastic flow solution,which satisfies the motion and continuity equations,is considered(with particular cases of exact solutions for pressure).The perturbed governing equations of motion for rivulet flows then result in the Riccati-type ordinary differential equation(ODE),describing the dynamics of the coordinate x(t).The approximated schematic dynamics are presented in graphical plots.
基金supported by the Qilu University of Technology(Shandong Academy of Sciences),the Basic Research Project of Science,Education and Industry Integration Pilot Project(No.2022PY047).
文摘Photothermal synergistic catalytic systems for treating volatile organic compounds(VOCs)have attracted signif-icant attention due to their energy efficiency and potential to reduce carbon emissions.However,the mechanism underlying the synergistic reaction remains a critical issue.This study introduces a photothermal synergistic system for the removal of ethyl acetate(EA)by synthesizing Cu-doped OMS-2(denoted as Cu-OMS-2).Under ultraviolet-visible(UV–Vis)irradiation in a flow system,the Cu-OMS-2 catalyst exhibited significantly enhanced performance in the EA degradation process,nearly doubling the effectiveness of pure OMS-2,and increasing carbon dioxide yield by 20%.This exceptional performance is attributed to the synergistic effect of increased oxygen vacancies(OV)at OMS-2 active sites and Cu doping,as confirmed by H2-TPR,O_(2)-TPD,and CO consump-tion measurements.This study clarifies the catalytic mechanism of light-assisted thermocatalysis and offers a novel strategy for designing photothermal catalysts with homogeneous Cu-doped nanorods for VOC removal.
基金support from the Science and Technology Innovation Program of Hunan Province(Grant No.2023RC1021)the Natural Science Foundation of Sichuan Province(Grant No.2025YFHZ0323).-。
文摘The coupled chemo-mechanical impact of supercritical CO_(2)-H_(2)O(ScCO_(2)-H_(2)O)reactions on fracture geometry and nonlinear flow regimes in deep shale under confining pressures remains inadequately quantified.This study systematically investigates the effects of ScCO_(2)-H_(2)O-shale interactions on fracture morphology and flow properties under confining pressures from 15 MPa to 40 MPa by integrating XRD(X-ray diffraction),micro-CT,3D surface profilometry,and multistage steady-state flow experiments.The results demonstrate that ScCO_(2)-H_(2)O exposure drives pyrite/feldspar dissolution and localized clay precipitation,resulting in fracture branching and macroscopic aperture regularization.Critically,confining pressure dictates the net hydraulic response:under low confining pressure(15-25 MPa),dissolution dominates,enhancing permeability,flow efficiency(Q/VP),and pre-linear flow behavior(n<1).At high confining pressures(30-40 MPa)mechanical compaction and mineral precipitation amplify flow resistance,shifting the flow regime toward quasi-linear behavior,as inertial effects become negligible compared to dominant viscous forces and increased flow resistance.Confining pressure thus critically mediates the dissolution-precipitation balance during ScCO_(2)-H_(2)O treatment,with an optimal window of 15-25 MPa identified for enhancing conductivity while minimizing clogging risk.These findings provide a quantitative framework for predicting stress-dependent flow evolution in chemically altered shale fractures.
基金financially supported by the National Natural Science Foundation of China(22578113 and 52371187)Natural Science Foundation of Hebei Province(E2024209029)Science and Technology Planning Project of Tangshan City(24130228C)。
文摘Vanadium redox flow battery(VRFB),as a potential technology for next-generation energy storage system,is restricted by the slow redox kinetics of vanadium ions.Implementing interface engineering strategies to functionalize the surface of MXene can effectively address this challenge.Herein,a Nb_(2)CT_(x)/Nb_(2)O_(5)Schottky heterostructure is constructed to facilitate high-speed charge transfer at the VRFB electrode through controllable in-situ oxidation.The loading amount of Nb_(2)O_(5) nanorods on the surface of Nb_(2)CT_(x) nanosheets was regulated by varying the hydrothermal reaction time.Density functional theory calculations confirm that the Schottky barrier formed between Nb_(2)CT_(x) and Nb_(2)O_(5) leads to the establishment of an internal electric field and reconfigures the electronic structure of surficial active sites.The rich pore structure of Nb_(2)CT_(x)/Nb_(2)O_(5) electrode effectively shortens the diffusion path for vanadium ions,while its excellent hydrophilicity enhances the interaction between vanadium ions and the electrodes.Compared with graphite felt,Nb_(2)CT_(x)/Nb_(2)O_(5)-2@GF cell shows a 20%increase in energy efficiency(EE)at 150 mA cm^(-2) cycling,reaching 75%,while maintaining stable performance for over 800 cycles.This means a significant advancement in the development of high-performance electrodes for VRFBs.This work offers an efficient and scalable strategy for the design of redox flow batteries.
文摘管道输送CO_(2)作为碳捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)产业链的关键环节之一,在海上CCUS发展中发挥着越来越重要的作用。高压密相CO_(2)管道泄压所造成的管道低温脆性断裂、干冰堵塞等问题,严重影响海上平台CO_(2)输送管道的安全运行。针对海上平台间高压密相CO_(2)管道,采用LedaFlow动态模拟软件建立CO_(2)输送管道泄压模型,分析海上冬季和夏季环境条件下管道沿程温度、压力和泄压量的变化趋势,并对比管道不同初始输送压力、初始输量和泄压对管道流体低温的影响情况。结果表明,冬季泄压造成的海底管道低温要比夏季泄压时低,故推荐在夏季进行泄压操作。在冬季最低环境温度条件下,适当减小泄压口径能够有效避免沿程温度、压力的大幅变化而导致的管道低温情况。研究成果可为实际海上高压密相CO_(2)输送管道的泄压操作提供参考。
文摘Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative permeability experiments on sandstone from a proposed storage site,comple-mented by in situ X-ray imaging and ex situ analyses using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).Despite our use of a brine that was pre-equilibrated with CO_(2),there was a significant reduction in both CO_(2) relative permeability and absolute permeability during multiphase flow due to chemical reactions.This reduction was driven by decreased pore and throat sizes,diminished connectivity,and increased irregularity of pore and throat shapes,as revealed by in situ pore-scale imaging.Mineral dissolution,primarily of feldspar,albite,and calcite,along with precipitation resulting from feldspar-to-kaolinite transformation and fines migration,were identified as contributing factors through SEM-EDS analysis.This work provides a benchmark for storage in mineralogically complex sandstones,for which the impact of chemical reactions on multiphase flow properties has been measured.
基金supported by the National Key R&D Program of China(2021YFF0500703)Natural Science Foundation of Shanghai(22JC1404200)+3 种基金Program of Shanghai Academic/Technology Research Leader(20XD1404000)Natural Science Foundation of China(U22B20136,22293023)Science and Technology Major Project of Inner Mongolia(2021ZD0042)the Youth Innovation Promotion Association of CAS。
文摘A radical C−C-coupling reaction of acetonitrile into succinonitrile over hydrophobic TiO_(2) photocatalyst with enhanced catalytic activity was developed.In addition,the usage of a flow reactor further improved the photon utilization efficiency for succinonitrile synthesis at room temperature.The space time yield of succinonitrile reached 55.59μmol/(g·h)over hydrophobic TiO_(2) catalyst,which was much higher than that of pristine TiO_(2)(4.23μmol/(g·h)).Mechanistic studies revealed that the hydrophobic modification of TiO_(2) promoted the separation and transfer of photogenerated carriers,as well as suppressed their recombination.Hydrophobic TiO_(2) also enhanced the adsorption of−CH3 of acetonitrile,thus facilitating the activation of C−H bond and the utilization efficiency of photocarriers.
基金supported by the National Natural Science Foundation of China(Nos.62175053,62305087)。
文摘The Görtler vortex is a characteristic flow feature observed in the boundary layer on compression ramp in hypersonic flow.In the context of high-enthalpy plasma flows during aerospace re-entry processes,there is currently a lack of effective means to visualize the boundary layer.In this study,the Nitric Oxide Planar Laser-Induced Fluorescence(NO-PLIF)technique was employed to visualize the boundary layer of a compression ramp in a 50-MW arc-heated plasma wind tunnel.Görtler-like vortex structures were observed in the boundary layer of the ramp.This is the first time that Görtler vortices have been clearly observed in a high-enthalpy plasma flow.By varying the flow conditions,the Görtler vortices persisted in the boundary layer of the ramp when the total enthalpy of the arc-heated wind tunnel exceeded 12.3 MJ/kg.Several image processing techniques were applied to extract the structure of high-speed Görtler streaks,and the position of the high-speed streaks was found to be non-fixed,whereas the average Görtler wavelength remained at approximately 30 mm at a 10°ramp and showed limited variation with the total enthalpy.Additionally,a sheet-forming optics system with an adjustable angle and height was designed to enable visualization of the Görtler vortices in the boundary layer of the ramp at different angles and heights.The vortices on the low-angle ramp exhibited better stability and shorter wavelengths.Visualization results at different heights confirmed that the Görtler vortex wavelength was approximately twice the boundary layer thickness.This study demonstrates the feasibility and potential of the PLIF technique for the visualization of the boundary layer in plasma flows,especially with regard to Görtler vortices.
基金supported by the National Natural Science Foundation of China(22272081 and 51802160)the Startup Foundation for Introducing Talent of NUIST(S8113082001).
文摘Global investment in ethylene(C_(2)H_(4))production via nonpetroleum pathways is rising,highlighting its growing importance in the energy and environmental sectors.The electroreduction of carbon dioxide(CO_(2))to C_(2)H_(4) inflow cells is emerging as a promising technology with broad practical applications.Direct delivery of gaseous CO_(2) to the cathode catalyst layer overcomes mass transfer limitations,enhancing reaction rates and enabling high current density.This review summarizes recent research progress in the electrocatalytic CO_(2) reduction reaction(eCO_(2)RR)for selective C_(2)H_(4) production inflow cells.It outlines the principles of eCO_(2)RR to C_(2)H_(4) and discusses the influence of copper-based catalyst morphology,crystal facet,oxidation state,surface modification strategy,and synergistic effects on catalytic performance.In addition,it highlights the compositional structure of theflow cell,and the selection and optimization of operating conditions,including gas diffusion electrodes,electrolytes,ion exchange membranes,and alternative anode reaction types beyond the oxygen evolution reaction.Finally,advances in machine learning are presented for accelerating catalyst screening and predicting dynamic changes in catalysts during reduction.This comprehensive review serves as a valuable reference for the development of efficient catalysts and the construction of electrolytic devices for the electrocatalytic reduction of CO_(2) to C_(2)H_(4).
文摘This study introduces a Transformer-based multimodal fusion framework for simulating multiphase flow and heat transfer in carbon dioxide(CO_(2))–water enhanced geothermal systems(EGS).The model integrates geological parameters,thermal gradients,and control schedules to enable fast and accurate prediction of complex reservoir dynamics.The main contributions are:(i)development of a workflow that couples physics-based reservoir simulation with a Transformer neural network architecture,(ii)design of physics-guided loss functions to enforce conservation of mass and energy,(iii)application of the surrogate model to closed-loop optimization using a differential evolution(DE)algorithm,and(iv)incorporation of economic performance metrics,such as net present value(NPV),into decision support.The proposed framework achieves root mean square error(RMSE)of 3–5%,mean absolute error(MAE)below 4%,and coefficients of determination greater than 0.95 across multiple prediction targets,including production rates,pressure distributions,and temperature fields.When compared with recurrent neural network(RNN)baselines such as gated recurrent units(GRU)and long short-term memory networks(LSTM),as well as a physics-informed reduced-order model,the Transformer-based approach demonstrates superior accuracy and computational efficiency.Optimization experiments further show a 15–20%improvement in NPV,highlighting the framework’s potential for real-time forecasting,optimization,and decision-making in geothermal reservoir engineering.
基金supported by the National Natural Science Foundation of China (Grant No.41272254 and No.41572215)
文摘CO_2 is now considered as a novel heat transmission fluid to extract geothermal energy. It can be used for both energy exploitation and CO_2 geological sequestration. Here, a 3-D, "two-spot" pattern well model is developed to analyze the mechanism of CO_2-water displacement and heat extraction. To obtain a deeper understanding of CO_2-geothermal system under some more realistic conditions, heterogeneity of reservoir's hydrological properties is taken into account. Due to the fortissimo mobility of CO_2, as long as the existence of highly permeable zone between the two wells, it is more likely to flow through the highly permeable zone to reach the production well, even though the flow path is longer. The preferential flow shortens circulation time and reduces heat-exchange area, probably leading to early thermal breakthrough, which makes the production fluid temperature decrease rapidly. The analyses of flow dynamics of CO_2-water fluid and heat may be useful for future design of a CO_2-based geothermal development system.
基金the support from the National Natural Science Foundation of China(No.52079077)Natural Science Foundation of Hubei Provincial(2025AFB358).
文摘Although extensive research has been conducted on CO_(2)-enhanced coalbed methane(CO_(2)-ECBM)recovery,most prior studies have focused on the impact of gas adsorption-induced swelling on coal permeability under equilibrium conditions.This paper presents a comprehensive thermo-hydro-mechanical-chemical(THMC)model that integrates thermal expansion and heat conduction(T),gas diffusion in the matrix and gas-water two-phase flow in the fractures(H),matrix and fracture deformation due to poroelasticity(M),and non-equilibrium binary gas adsorption-induced matrix swelling(C)during CO_(2)-ECBM recovery.The accuracy of the proposed model was verified through experimental data,and the model was simulated using finite element method(FEM)software.Simulation results indicate that the permeability evolution can be categorized into three stages.Ignoring the impact of water on gas adsorption properties would lead to an overestimation of the influence of adsorption-induced swelling,while disregarding non-equilibrium adsorption underestimates it.An examination of five designed cases identified critical factors influencing permeability.Parametric analysis shows that increases in the injection pressure,the injection temperature,and the initial permeability promote the competitive adsorption-induced swelling between CH_(4)and CO_(2),leading to increased CH_(4)production and CO_(2)storage.Conversely,an increase in initial water saturation reduces available gas flow space,decreasing both CH_(4)production and CO_(2)storage.Higher irreducible water saturation favors early gas recovery,while lower irreducible water saturation is more advantageous for long-term recovery.
基金supports from the National Natural Science Foundation of China(Grant Nos.52179095,52378323,and 42407216)are gratefully acknowledged.
文摘The increase in CO_(2)injectivity and shifting of CO_(2)-absorbing layers in multilayered geological CO_(2)sequestration(GCS)reservoirs in Ordos,China indicate significantpermeability variations in certain layers.To capture these system changes,a numerical model incorporating all 21 aquifers and internal aquitards was developed.The monitored pressure was well matched through multiphase and thermalhydraulic-mechanical(THM)coupling numerical simulations by introducing permeability variations.The results revealed that the permeability in the second layer increased on approximately day 13 due to the abrupt pressure buildup and temperature decrease.Even such a low rate of CO_(2)(2.8 kg/s)injected into the low permeability system initiated some fractures and the permeability in the second layer around the wellbore increased by 722 times.The second critical system change occurred on approximately day 386.As demonstrated in the numerical simulation,the substantial injection of cold CO_(2)induced strong thermal stress,leading to rock contraction and the initiation of several cracks.The permeability of the firstlayer around the wellbore unexpectedly increased by 4 orders of magnitude.Since no additional pressure could drive the CO_(2)into the remaining 17 layers,the total storage capability of the multilayered system was reduced.A whole picture of the system variation is fully presented and the underlying mechanisms are analyzed.It is believed that the phenomenon of thermal-hydraulic fracturing observed in this fieldand the simulation procedures will benefitother fluidinjection and production works in various geotechnical settings.
