This paper introduces MultiPHydro,an in-house computational solver developed for simulating hydrodynamic and multiphase fluid—body interaction problems,with a specialized focus on multiphase flow dynamics.The solver ...This paper introduces MultiPHydro,an in-house computational solver developed for simulating hydrodynamic and multiphase fluid—body interaction problems,with a specialized focus on multiphase flow dynamics.The solver employs the boundary data immersion method(BDIM)as its core numerical framework for handling fluid—solid interfaces.We briefly outline the governing equations and physical models integrated within MultiPHydro,including weakly-compressible flows,cavitation modeling,and the volume of fluid(VOF)method with piecewise-linear interface reconstruction.The solver’s accuracy and versatility are demonstrated through several numerical benchmarks:single-phase flow past a cylinder shows less than 10%error in vortex shedding frequency and under 4%error in hydrodynamic resistance;cavitating flows around a hydrofoil yield errors below 7%in maximum cavity length;water-entry cases exhibit under 5%error in displacement and velocity;and water-exit simulations predict cavity length within 7.2%deviation.These results confirm the solver’s capability to reliably model complex fluid-body interactions across various regimes.Future developments will focus on refining mathematical models,improving the modeling of phase-interaction mechanisms,and implementing GPU-accelerated parallel algorithms to enhance compatibility with domestically-developed operating systems and deep computing units(DCUs).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
Multiphase flows widely exist in various scientific and engineering fields,and strongly compressible multiphase flows commonly occur in practical applications,which makes them an important part of computational fluid ...Multiphase flows widely exist in various scientific and engineering fields,and strongly compressible multiphase flows commonly occur in practical applications,which makes them an important part of computational fluid dynamics.In this study,an axisymmetric adaptive multiresolution smooth particle hydrodynamics(SPH)model is proposed to solve various strongly compressible multiphase flow problems.In the present model,the governing equations are discretized in cylindrical polar coordinates,and an improved volume adaptive scheme is developed to better solve the problem of excessive volume change in strongly compressible multiphase flows.On this basis,combined with the adaptive particle refinement technique,an adaptive multiresolution scheme is proposed in this study.In addition,the high-order differential operator and diffusion correction term are utilized to improve the accuracy and stability.The effectiveness of the model is verified by testing four typical strongly compressible multiphase flow problems.By comparing the results of adaptive multiresolution SPH with other numerical results or experimental data,we can conclude that the present SPH method effectively models strongly compressible multiphase flows.展开更多
Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate pro-duction.The present work involves the development of a multiphase gas-liquid-solid vertical slug ...Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate pro-duction.The present work involves the development of a multiphase gas-liquid-solid vertical slug flow hydrodynamic model consi-dering hydrate phase transition kinetics with heat and mass transfer behaviors.The varying gas physical properties due to pressure and temperature variations are also introduced to evaluate vertical slug flow characteristics.The proposed model is used to carry out a series of numerical simulations to examine the interactions between hydrate phase transition and vertical slug flow hydrodynamics.Furthermore,the hydrate volumetric fractions under different pressure and temperature conditions are predicted.The results reveal that hydrate formation and gas expansion cause the mixture superficial velocity,and the gas and liquid fractions,void fraction in liq-uid slug,and unit length tend to decrease.The increase in outlet pressure leads to an increased hydrate formation rate,which not only increases the hydrate volumetric fraction along the pipe but also causes the upward shift of the hydrate phase transition critical point.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
The majority of published empirical correlations and mechanistic models are unable to provide accurate flowing bottom-hole pressure(FBHP)predictions when real-time field well data are used.This is because the empirica...The majority of published empirical correlations and mechanistic models are unable to provide accurate flowing bottom-hole pressure(FBHP)predictions when real-time field well data are used.This is because the empirical correlations and the empirical closure correlations for the mechanistic models were developed with experimental datasets.In addition,most machine learning(ML)FBHP prediction models were constructed with real-time well data points and published without any visible mathematical equation.This makes it difficult for other readers to use these ML models since the datasets used in their development are not open-source.This study presents a white-box adaptive neuro-fuzzy inference system(ANFIS)model for real-time prediction of multiphase FBHP in wellbores.1001 real well data points and 1001 normalized well data points were used in constructing twenty-eight different Takagi eSugeno fuzzy inference systems(FIS)structures.The dataset was divided into two sets;80%for training and 20%for testing.Statistical performance analysis showed that a FIS with a 0.3 range of influence and trained with a normalized dataset achieved the best FBHP prediction performance.The optimal ANFIS black-box model was then translated into the ANFIS white-box model with the Gaussian input and the linear output membership functions and the extracted tuned premise and consequence parameter sets.Trend analysis revealed that the novel ANFIS model correctly simulates the anticipated effect of input parameters on FBHP.In addition,graphical and statistical error analyses revealed that the novel ANFIS model performed better than published mechanistic models,empirical correlations,and machine learning models.New training datasets covering wider input parameter ranges should be added to the original training dataset to improve the model's range of applicability and accuracy.展开更多
A 3D mathematical model was proposed to investigate the molten steel–slag–air multiphase flow in a two-strand slab continuous casting(CC)tundish during ladle change.The study focused on the exposure of the molten st...A 3D mathematical model was proposed to investigate the molten steel–slag–air multiphase flow in a two-strand slab continuous casting(CC)tundish during ladle change.The study focused on the exposure of the molten steel and the subsequent reoxidation occurrence.The exposure of the molten steel was calculated using the coupled realizable k–εmodel and volume of fluid(VOF)model.The diffusion of dissolved oxygen was determined by solving the user-defined scalar(UDS)equation.Moreover,the user-defined function(UDF)was used to describe the source term in the UDS equation and determine the oxidation rate and oxidation position.The effect of the refilling speed on the molten steel exposure and dissolved oxygen content was also discussed.Increasing the refilling speed during ladle change reduced the refilling time and the exposure duration of the molten steel.However,the elevated refilling speed enlarged the slag eyes and increased the average dissolved oxygen content within the tundish,thereby exacerbating the reoxidation phenomenon.In addition,the time required for the molten steel with a high dissolved oxygen content to exit the tundish varied with the refilling speed.When the inlet speed was 3.0 m·s^(-1)during ladle change,the molten steel with a high dissolved oxygen content exited the outlet in a short period,reaching a maximum dissolved oxygen content of 0.000525wt%.Conversely,when the inlet speed was 1.8 m·s^(-1),the maximum dissolved oxygen content was 0.000382wt%.The refilling speed during the ladle change process must be appropriately decreased to minimize reoxidation effects and enhance the steel product quality.展开更多
This paper aims to tackle the calculation efficiency problem raised in the cavitation-flow simulation of the aviation centrifugal pump due to the fading-away interface resulting from the dissipation of numerics used i...This paper aims to tackle the calculation efficiency problem raised in the cavitation-flow simulation of the aviation centrifugal pump due to the fading-away interface resulting from the dissipation of numerics used in the phase-change control equation for unstructured-grid multiphase flow,and due to the limitation of flow time-step in whole flow regimes,the control equation of vapor–liquid two-phase flow considering cavitation mass transport is established firstly,modifying the momentum equation by introducing the surface tension,and adding the artificial convective flow to the phase equation to solve the numerical dissipation problem.Secondly,in consideration of the local time step principle and based on the multi-dimensional general limiter algorithm with explicit solutions under the OpenFOAM platform,a solution method of steady-state VOF (Volume of Fluid) model considering cavitation two-phase change is constructed,and the feasibility of this method is verified by NACA hydrofoil and NASA flat plate inducer.Finally,based on the platform developed,the cavitation performance of an aviation centrifugal pump inducer is analyzed.The research results show that the error of the calculated cavitation pressure distribution for NACA hydrofoil between the simulation test and the experimental-test is less than 5%,and the maximum error of calculated cavitation number at pump head dropping for NASA high-speed flat plate inducer between the simulation test and the experimental-test is 2.1%.The cavitation area observed in the simulation test is the same as that obtained in the high-speed photography test.Based on the OpenFOAM simulation method,the position of pump head dropping of the fuel centrifugal pump can be accurately captured.The error of the calculated cavitation number at pump head dropping between the simulation test and the experimental test is about 3.7%,showing high calculation accuracy.展开更多
A multiphase field model coupled with a lattice Boltzmann(PF-LBM)model is proposed to simulate the distribution mechanism of bubbles and solutes at the solid-liquid interface,the interaction between dendrites and bubb...A multiphase field model coupled with a lattice Boltzmann(PF-LBM)model is proposed to simulate the distribution mechanism of bubbles and solutes at the solid-liquid interface,the interaction between dendrites and bubbles,and the effects of different temperatures,anisotropic strengths and tilting angles on the solidified organization of the SCN-0.24wt.%butanedinitrile alloy during the solidification process.The model adopts a multiphase field model to simulate the growth of dendrites,calculates the growth motions of dendrites based on the interfacial solute equilibrium;and adopts a lattice Boltzmann model(LBM)based on the Shan-Chen multiphase flow to simulate the growth and motions of bubbles in the liquid phase,which includes the interaction between solid-liquid-gas phases.The simulation results show that during the directional growth of columnar dendrites,bubbles first precipitate out slowly at the very bottom of the dendrites,and then rise up due to the different solid-liquid densities and pressure differences.The bubbles will interact with the dendrite in the process of flow migration,such as extrusion,overflow,fusion and disappearance.In the case of wide gaps in the dendrite channels,bubbles will fuse to form larger irregular bubbles,and in the case of dense channels,bubbles will deform due to the extrusion of dendrites.In the simulated region,as the dendrites converge and diverge,the bubbles precipitate out of the dendrites by compression and diffusion,which also causes physical phenomena such as fusion and spillage of the bubbles.These results reveal the physical mechanisms of bubble nucleation,growth and kinematic evolution during solidification and interaction with dendrite growth.展开更多
During perfusion culture,the growth of bone tissues in the scaffold was closely related to the locations of initial adhered cells and their density.In this study,the fluid mechanical responses of Voronoi-lattice scaff...During perfusion culture,the growth of bone tissues in the scaffold was closely related to the locations of initial adhered cells and their density.In this study,the fluid mechanical responses of Voronoi-lattice scaffolds and initial adhered cells on scaffolds were quantitatively investigated.Multiphase fluid-structure interaction(FSI)model was verified by comparing with the results of Diamond scaffolds culture in the literature.Fluid mechanical responses of Voronoi-lattice scaffolds and cells were analyzed by multiphase FSI model.Regression equations were established by response surface method(RSM)to determine relationships between structural design factors of Voronoi-lattice scaffolds and fluid mechanical response parameters of scaffolds and cells.The results showed that the percentage of adhered cells and the locations of initial adhered cells obtained by multiphase FSI model of Diamond scaffolds had the same trend with that obtained by perfusion culture.Regression equations established based on RSM could well predict the fluid mechanical response parameters of Voronoi-scaffolds and cells.The multiphase FSI model closely related the densities of cells and the locations of adhered cells to bone tissue growth.The model could provide a certain theoretical basis for constructing and culturing engineered bone tissues in vitro perfusion.展开更多
Surfactants are widely used in the fracturing fluid to enhance the imbibition and thus the oil recovery rate. However, current numerical models cannot capture the physics behind capillary imbibition during the wettabi...Surfactants are widely used in the fracturing fluid to enhance the imbibition and thus the oil recovery rate. However, current numerical models cannot capture the physics behind capillary imbibition during the wettability alteration by surfactants. Although the interacting capillary bundle(ICB) model shows potential in characterizing imbibition rates in different pores during wettability alteration, the existing ICB models neglect the influence of wettability and viscosity ratio on the imbibition behavior, making it difficult to accurately describe the oil-water imbibition behavior within the porous media. In this work,a new ICB mathematical model is established by introducing pressure balance without assuming the position of the leading front to comprehensively describe the imbibition behavior in a porous medium under different conditions, including gas-liquid spontaneous imbibition and oil-water imbibition.When the pore size distribution of a tight rock is known, this new model can predict the changes of water saturation during the displacement process in the tight rock, and also determine the imbibition rate in pores of different sizes. The water saturation profiles obtained from the new model are validated against the waterflooding simulation results from the CMG, while the imbibition rates calculated by the model are validated against the experimental observations of gas-liquid spontaneous imbibition. The good match above indicates the newly proposed model can show the water saturation profile at a macroscopic scale while capture the underlying physics of the multiphase flow in a porous medium at a microscopic scale. Simulation results obtained from this model indicate that both wettability and viscosity ratio can affect the sequence of fluid imbibition into pores of different sizes during the multiphase flow, where less-viscous wetting fluid is preferentially imbibed into larger pores while more-viscous wetting fluid tends to be imbibed into smaller pores. Furthermore, this model provides an avenue to calculate the imbibition rate in pores of different sizes during wettability alteration and capture the non-Darcy effect in micro-and nano-scale pores.展开更多
Considering the phase behaviors in condensate gas reservoirs and the oil-gas two-phase linear flow and boundary-dominated flow in the reservoir,a method for predicting the relationship between oil saturation and press...Considering the phase behaviors in condensate gas reservoirs and the oil-gas two-phase linear flow and boundary-dominated flow in the reservoir,a method for predicting the relationship between oil saturation and pressure in the full-path of tight condensate gas well is proposed,and a model for predicting the transient production from tight condensate gas wells with multiphase flow is established.The research indicates that the relationship curve between condensate oil saturation and pressure is crucial for calculating the pseudo-pressure.In the early stage of production or in areas far from the wellbore with high reservoir pressure,the condensate oil saturation can be calculated using early-stage production dynamic data through material balance models.In the late stage of production or in areas close to the wellbore with low reservoir pressure,the condensate oil saturation can be calculated using the data of constant composition expansion test.In the middle stages of production or when reservoir pressure is at an intermediate level,the data obtained from the previous two stages can be interpolated to form a complete full-path relationship curve between oil saturation and pressure.Through simulation and field application,the new method is verified to be reliable and practical.It can be applied for prediction of middle-stage and late-stage production of tight condensate gas wells and assessment of single-well recoverable reserves.展开更多
A three-dimensional mathematical model has been established for a novel metallurgy process coupling an annular gas curtain with swirling flow at tundish upper nozzle. The discrete phase model and volume of fluid model...A three-dimensional mathematical model has been established for a novel metallurgy process coupling an annular gas curtain with swirling flow at tundish upper nozzle. The discrete phase model and volume of fluid model were applied to simulate the gas–liquid multiphase flow behavior in tundish and nozzle. The effect of argon flow rate on the migration behavior of bubbles and interface behavior between steel and slag was also investigated. The presented results indicate that the novel coupling process can significantly change the flow pattern in the stream zone of a tundish, prolong the average residence time of liquid steel, and reduce the dead fraction. A complete annular gas curtain is formed around the stopper rod of tundish. Under the action of drag force of liquid steel, a part of small bubbles enter the nozzle through the swirling grooves and gather toward the center of the nozzle by centripetal force. As the argon flow rate increases, the volume fraction of argon gas entering the nozzle increases, which enhances the swirl intensity and increases the concentration of bubbles in the nozzle. To avoid the formation of slag open eye in tundish, the argon flow rate should not exceed 8 L min−1.展开更多
In order to check the validity of the mathematical model for analyzing the flow field in the air-agitated seed precipitation tank,a scaled down experimental apparatus was designed and the colored tracer and KCl tracer...In order to check the validity of the mathematical model for analyzing the flow field in the air-agitated seed precipitation tank,a scaled down experimental apparatus was designed and the colored tracer and KCl tracer were added in the apparatus to follow the real flow line.Virtue tracers were considered in the mathematical model and the algorithm of tracers was built.The comparison of the results between the experiment and numerical calculation shows that the time of the tracer flows out of stirring tube are 40 s in the experiment and 42 s in numerical calculated result.The transient diffusion process and the solution residence time of the numerical calculation are in good agreement with the experimental results,which indicates that the mathematical model is reliable and can be used to predict the flow field of the air-agitated seed precipitation tank.展开更多
This review summarizes recent progress in the study of impinging-jet dynamics and atomization,with a focus on liquid sheet formation,instability mechanisms,and the influence of key parameters such as fluid properties,...This review summarizes recent progress in the study of impinging-jet dynamics and atomization,with a focus on liquid sheet formation,instability mechanisms,and the influence of key parameters such as fluid properties,Weber number,and Reynolds number.Special attention is given to atomization behaviors under high pressure and external perturbations.Representative experimental and numerical approaches are introduced,and critical findings under complex conditions are highlighted.In addition,practical applications of impinging-jet technology in aerospace propulsion,biomedical devices,and energy science are discussed.This review aims to serve as a concise reference for researchers interested in multiphase flow dynamics and engineering applications of impinging jets.展开更多
A floating horizontal-axis tidal current turbine(HATT)is an underwater power generation device where cavitation inevitably occurs on blade surfaces,severely affecting a turbine’s lifespan.Under wave action,these floa...A floating horizontal-axis tidal current turbine(HATT)is an underwater power generation device where cavitation inevitably occurs on blade surfaces,severely affecting a turbine’s lifespan.Under wave action,these floating turbines exhibit six degrees of freedom motion,potentially intensifying the cavitation on the blade surfaces.This study selects three types of oscillatory motions from the six degrees of freedom:roll,yaw,and pitch.Computational fluid dynamics(CFD)methods are used for numerical calculations,and transient simulations of multiphase flow are conducted on the basis of the Reynolds-Averaged Navier-Stokes(RANS)model.Research has revealed strong correlations between flow velocity,the blade tip speed ratio,and cavitation.During oscillatory motion,the motion period and amplitude also significantly impact cavitation.In roll motion,the cavitation rate can increase by up to 59%with decreasing period,whereas in pitch and yaw motions,the increases are 7.57 times and 36%larger,respectively.With an increase in amplitude during roll motion,the cavitation rate can increase by up to 1.08 times,whereas in pitch and yaw motions,the increases are 3.49 times and 45%,respectively.The cavitation rate on the blade surfaces is the highest in pitch motion,followed by roll and yaw motions.展开更多
Submarine landslides frequently occur on continental margins and slopes,thereby causing serious damage to offshore structures.Therefore,analyzing their motion behavior and predicting their impact forces are crucial.In...Submarine landslides frequently occur on continental margins and slopes,thereby causing serious damage to offshore structures.Therefore,analyzing their motion behavior and predicting their impact forces are crucial.In this work,the smooth particle hydrodynamics(SPH)algorithm is used in the development of a multiphase flow model for submarine landslides.The underwater landslide and the ambient water are simulated using the non-Newtonian and Newtonian fluid models,respectively.An artificial diffusion term of density is incorporated in the governing equation,and the equation of state is modified to improve the stability and accuracy of the SPH model.Three benchmark problems are simulated using the SPH model.The effect of SPH particle size on the simulated results is also explored.The effects of the rheological parameters on the landslide motion behavior are investigated by conducting a sensitivity analysis.Numerical results fit the experimental data well,indicating the good stability of the SPH model and its accuracy in simulating the motion and impact behavior of submarine landslides.展开更多
The gas kick represents a major risk in deepwater oil and gas exploration.Understanding the dynamics of gas kick evolution and the associated pressure response characteristics is critical for effective well control.In...The gas kick represents a major risk in deepwater oil and gas exploration.Understanding the dynamics of gas kick evolution and the associated pressure response characteristics is critical for effective well control.In this paper,we introduce a transient wellbore multiphase flow model specifically developed to simulate gas kick in deepwater dual-gradient drilling,incorporating a downhole separator.The model accounts for the variable mass flow within the annulus and heat exchange between the annular fluid and the formation.Using this model,we analyzed the multiphase flow and thermodynamic behavior during the gas kick.Simulation results reveal a progressive increase in bottom-hole temperature,underscoring its potential as a key indicator for gas kick early detection.Additionally,variable gradient parameters affect not only the annular equivalent circulating density(ECD)profile but also the evolution of the gas kick.The inclusion of a downhole separator alters the annular ECD profile,creating a“broken line”shape,which enhances adaptability to the multi-pressure systems typically encountered in deepwater forma-tion.By adjusting factors such as hollow sphere concentration,separator position,and separation effi-ciency,the annular ECD profile can be effectively customized.This study provides important theoretical insights and practical applications for utilizing dual-gradient drilling technology to address challenges in deepwater formation drilling.展开更多
High-pressure water jet technology has emerged as a highly effective method for removing industrial-scale deposits from pipelines,offering a clean,efficient,and environmentally sustainable alternative to conventional ...High-pressure water jet technology has emerged as a highly effective method for removing industrial-scale deposits from pipelines,offering a clean,efficient,and environmentally sustainable alternative to conventional mechanical or chemical cleaning techniques.Among the many parameters influencing its performance,the geometry of the nozzle plays a decisive role in governing jet coherence,impact pressure distribution,and overall cleaning efficiency.In this study,a comprehensive numerical and experimental investigation is conducted to elucidate the influence of nozzle geometry on the behavior of high-pressure water jets.Using Computational Fluid Dynamics(CFD)simulations based on the Volume of Fluid(VOF)approach,the jet dynamics and impingement characteristics of three representative nozzle configurations—flat,conical,and tapered—are systematically analyzed.Particular attention is devoted to the tapered nozzle,where variations in the outlet diameter are explored to determine their effect on flow structure,jet stability,and impact performance.The numerical predictions are rigorously validated against experimental measurements,demonstrating excellent quantitative agreement and confirming the robustness of the computational model.Results show that the tapered nozzle,characterized by its elongated conical transition section,promotes a more stable jet core and superior efflux performance compared to flat and conical geometries.Furthermore,the exit diameter is found to exert a profound influence on jet development.At an inlet pressure of 130 MPa,increasing the tapered nozzle's outlet diameter from 0.8 mm to 1.2 mm enlarges the coherent core region,enhances jet stability,and improves hydraulic energy utilization.Under these conditions,the total impact pressure on the target surface increases by 33.14%,while the overall cleaning efficiency improves by 40.44%.展开更多
Icing of water droplets is a ubiquitous phenomenon with significant implications across natural systems and industrial applications.Despite extensive research,the intricate interplay among heat transfer,mass transport...Icing of water droplets is a ubiquitous phenomenon with significant implications across natural systems and industrial applications.Despite extensive research,the intricate interplay among heat transfer,mass transport,and phase change during droplet freezing remains incompletely understood,particularly in the context of multiscale dynamics and environmental dependencies.This review critically examines recent advances in uncovering the fundamental mechanisms of droplet icing through experimental,theoretical,and computational approaches.We begin by revisiting the classical tip singularity problem in the freezing of pure water droplets,analyzing its mathematical formulation and physical significance.Subsequent sections explore how environmental boundary conditions and multicomponent effects influence freezing kinetics,solute redistribution,and ice morphology.Furthermore,we evaluate emerging hybrid numerical frameworks that resolve coupled multiphase physics during solidification processes.Finally,we identify key challenges and open questions that require further investigation in this field.展开更多
文摘This paper introduces MultiPHydro,an in-house computational solver developed for simulating hydrodynamic and multiphase fluid—body interaction problems,with a specialized focus on multiphase flow dynamics.The solver employs the boundary data immersion method(BDIM)as its core numerical framework for handling fluid—solid interfaces.We briefly outline the governing equations and physical models integrated within MultiPHydro,including weakly-compressible flows,cavitation modeling,and the volume of fluid(VOF)method with piecewise-linear interface reconstruction.The solver’s accuracy and versatility are demonstrated through several numerical benchmarks:single-phase flow past a cylinder shows less than 10%error in vortex shedding frequency and under 4%error in hydrodynamic resistance;cavitating flows around a hydrofoil yield errors below 7%in maximum cavity length;water-entry cases exhibit under 5%error in displacement and velocity;and water-exit simulations predict cavity length within 7.2%deviation.These results confirm the solver’s capability to reliably model complex fluid-body interactions across various regimes.Future developments will focus on refining mathematical models,improving the modeling of phase-interaction mechanisms,and implementing GPU-accelerated parallel algorithms to enhance compatibility with domestically-developed operating systems and deep computing units(DCUs).
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 Guangxi Natural Science Foundation(Grant No.2021GXNSFBA196008)the Guangxi Science and Technology Development Program(Grant No.GuikeAD22035189).
文摘Multiphase flows widely exist in various scientific and engineering fields,and strongly compressible multiphase flows commonly occur in practical applications,which makes them an important part of computational fluid dynamics.In this study,an axisymmetric adaptive multiresolution smooth particle hydrodynamics(SPH)model is proposed to solve various strongly compressible multiphase flow problems.In the present model,the governing equations are discretized in cylindrical polar coordinates,and an improved volume adaptive scheme is developed to better solve the problem of excessive volume change in strongly compressible multiphase flows.On this basis,combined with the adaptive particle refinement technique,an adaptive multiresolution scheme is proposed in this study.In addition,the high-order differential operator and diffusion correction term are utilized to improve the accuracy and stability.The effectiveness of the model is verified by testing four typical strongly compressible multiphase flow problems.By comparing the results of adaptive multiresolution SPH with other numerical results or experimental data,we can conclude that the present SPH method effectively models strongly compressible multiphase flows.
基金supported by the National Natural Science Foundation of China(No.52301355)the Natu-ral Science Foundation of Qingdao Municipality(No.23-2-1-108-zyyd-jch)the China University of Petroleum(East China)Independent Innovation Research Project(Science and Engineering)-Leading Talent Cultivation Fund(No.24CX07001A).
文摘Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate pro-duction.The present work involves the development of a multiphase gas-liquid-solid vertical slug flow hydrodynamic model consi-dering hydrate phase transition kinetics with heat and mass transfer behaviors.The varying gas physical properties due to pressure and temperature variations are also introduced to evaluate vertical slug flow characteristics.The proposed model is used to carry out a series of numerical simulations to examine the interactions between hydrate phase transition and vertical slug flow hydrodynamics.Furthermore,the hydrate volumetric fractions under different pressure and temperature conditions are predicted.The results reveal that hydrate formation and gas expansion cause the mixture superficial velocity,and the gas and liquid fractions,void fraction in liq-uid slug,and unit length tend to decrease.The increase in outlet pressure leads to an increased hydrate formation rate,which not only increases the hydrate volumetric fraction along the pipe but also causes the upward shift of the hydrate phase transition critical point.
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.
文摘The majority of published empirical correlations and mechanistic models are unable to provide accurate flowing bottom-hole pressure(FBHP)predictions when real-time field well data are used.This is because the empirical correlations and the empirical closure correlations for the mechanistic models were developed with experimental datasets.In addition,most machine learning(ML)FBHP prediction models were constructed with real-time well data points and published without any visible mathematical equation.This makes it difficult for other readers to use these ML models since the datasets used in their development are not open-source.This study presents a white-box adaptive neuro-fuzzy inference system(ANFIS)model for real-time prediction of multiphase FBHP in wellbores.1001 real well data points and 1001 normalized well data points were used in constructing twenty-eight different Takagi eSugeno fuzzy inference systems(FIS)structures.The dataset was divided into two sets;80%for training and 20%for testing.Statistical performance analysis showed that a FIS with a 0.3 range of influence and trained with a normalized dataset achieved the best FBHP prediction performance.The optimal ANFIS black-box model was then translated into the ANFIS white-box model with the Gaussian input and the linear output membership functions and the extracted tuned premise and consequence parameter sets.Trend analysis revealed that the novel ANFIS model correctly simulates the anticipated effect of input parameters on FBHP.In addition,graphical and statistical error analyses revealed that the novel ANFIS model performed better than published mechanistic models,empirical correlations,and machine learning models.New training datasets covering wider input parameter ranges should be added to the original training dataset to improve the model's range of applicability and accuracy.
基金the National Key R&D Program(No.2023YFB3709900)the National Natural Science Foundation of China(Nos.U22A20171 and 52104343)the High Steel Central(HSC)at North China University of Science and Technology and Yanshan Univ ersity,China。
文摘A 3D mathematical model was proposed to investigate the molten steel–slag–air multiphase flow in a two-strand slab continuous casting(CC)tundish during ladle change.The study focused on the exposure of the molten steel and the subsequent reoxidation occurrence.The exposure of the molten steel was calculated using the coupled realizable k–εmodel and volume of fluid(VOF)model.The diffusion of dissolved oxygen was determined by solving the user-defined scalar(UDS)equation.Moreover,the user-defined function(UDF)was used to describe the source term in the UDS equation and determine the oxidation rate and oxidation position.The effect of the refilling speed on the molten steel exposure and dissolved oxygen content was also discussed.Increasing the refilling speed during ladle change reduced the refilling time and the exposure duration of the molten steel.However,the elevated refilling speed enlarged the slag eyes and increased the average dissolved oxygen content within the tundish,thereby exacerbating the reoxidation phenomenon.In addition,the time required for the molten steel with a high dissolved oxygen content to exit the tundish varied with the refilling speed.When the inlet speed was 3.0 m·s^(-1)during ladle change,the molten steel with a high dissolved oxygen content exited the outlet in a short period,reaching a maximum dissolved oxygen content of 0.000525wt%.Conversely,when the inlet speed was 1.8 m·s^(-1),the maximum dissolved oxygen content was 0.000382wt%.The refilling speed during the ladle change process must be appropriately decreased to minimize reoxidation effects and enhance the steel product quality.
基金supported by the National Science and Technology Major Project, China (No. J2019-V-0016-0111)the Aviation Engine and Gas Turbine Basic Science Center Project, China (No. P2022-B-V-003-001)+3 种基金the Defense Industrial Technology Development Program, China (No. JCKY2022607C002)the AECC Industry University Cooperation Project, China (No. HFZL2022CXY013)the National Natural Science Foundation of China (No. 52372396)the Key R&D Project in Shaanxi Province, China (No. 2021GXLH-01-16)。
文摘This paper aims to tackle the calculation efficiency problem raised in the cavitation-flow simulation of the aviation centrifugal pump due to the fading-away interface resulting from the dissipation of numerics used in the phase-change control equation for unstructured-grid multiphase flow,and due to the limitation of flow time-step in whole flow regimes,the control equation of vapor–liquid two-phase flow considering cavitation mass transport is established firstly,modifying the momentum equation by introducing the surface tension,and adding the artificial convective flow to the phase equation to solve the numerical dissipation problem.Secondly,in consideration of the local time step principle and based on the multi-dimensional general limiter algorithm with explicit solutions under the OpenFOAM platform,a solution method of steady-state VOF (Volume of Fluid) model considering cavitation two-phase change is constructed,and the feasibility of this method is verified by NACA hydrofoil and NASA flat plate inducer.Finally,based on the platform developed,the cavitation performance of an aviation centrifugal pump inducer is analyzed.The research results show that the error of the calculated cavitation pressure distribution for NACA hydrofoil between the simulation test and the experimental-test is less than 5%,and the maximum error of calculated cavitation number at pump head dropping for NASA high-speed flat plate inducer between the simulation test and the experimental-test is 2.1%.The cavitation area observed in the simulation test is the same as that obtained in the high-speed photography test.Based on the OpenFOAM simulation method,the position of pump head dropping of the fuel centrifugal pump can be accurately captured.The error of the calculated cavitation number at pump head dropping between the simulation test and the experimental test is about 3.7%,showing high calculation accuracy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52161002,51661020,and 11364024)the Postdoctoral Science Foundation of China(Grant No.2014M560371)the Funds for Distinguished Young Scientists of Lanzhou University of Technology of China(Grant No.J201304).
文摘A multiphase field model coupled with a lattice Boltzmann(PF-LBM)model is proposed to simulate the distribution mechanism of bubbles and solutes at the solid-liquid interface,the interaction between dendrites and bubbles,and the effects of different temperatures,anisotropic strengths and tilting angles on the solidified organization of the SCN-0.24wt.%butanedinitrile alloy during the solidification process.The model adopts a multiphase field model to simulate the growth of dendrites,calculates the growth motions of dendrites based on the interfacial solute equilibrium;and adopts a lattice Boltzmann model(LBM)based on the Shan-Chen multiphase flow to simulate the growth and motions of bubbles in the liquid phase,which includes the interaction between solid-liquid-gas phases.The simulation results show that during the directional growth of columnar dendrites,bubbles first precipitate out slowly at the very bottom of the dendrites,and then rise up due to the different solid-liquid densities and pressure differences.The bubbles will interact with the dendrite in the process of flow migration,such as extrusion,overflow,fusion and disappearance.In the case of wide gaps in the dendrite channels,bubbles will fuse to form larger irregular bubbles,and in the case of dense channels,bubbles will deform due to the extrusion of dendrites.In the simulated region,as the dendrites converge and diverge,the bubbles precipitate out of the dendrites by compression and diffusion,which also causes physical phenomena such as fusion and spillage of the bubbles.These results reveal the physical mechanisms of bubble nucleation,growth and kinematic evolution during solidification and interaction with dendrite growth.
基金supported by the National Natural Science Foundation of China(Grant No.12272029).
文摘During perfusion culture,the growth of bone tissues in the scaffold was closely related to the locations of initial adhered cells and their density.In this study,the fluid mechanical responses of Voronoi-lattice scaffolds and initial adhered cells on scaffolds were quantitatively investigated.Multiphase fluid-structure interaction(FSI)model was verified by comparing with the results of Diamond scaffolds culture in the literature.Fluid mechanical responses of Voronoi-lattice scaffolds and cells were analyzed by multiphase FSI model.Regression equations were established by response surface method(RSM)to determine relationships between structural design factors of Voronoi-lattice scaffolds and fluid mechanical response parameters of scaffolds and cells.The results showed that the percentage of adhered cells and the locations of initial adhered cells obtained by multiphase FSI model of Diamond scaffolds had the same trend with that obtained by perfusion culture.Regression equations established based on RSM could well predict the fluid mechanical response parameters of Voronoi-scaffolds and cells.The multiphase FSI model closely related the densities of cells and the locations of adhered cells to bone tissue growth.The model could provide a certain theoretical basis for constructing and culturing engineered bone tissues in vitro perfusion.
基金financially supported by the General Program Grant from the National Natural Science Foundation of China(52274051 and 52174045)the Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020-01)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(51521063)。
文摘Surfactants are widely used in the fracturing fluid to enhance the imbibition and thus the oil recovery rate. However, current numerical models cannot capture the physics behind capillary imbibition during the wettability alteration by surfactants. Although the interacting capillary bundle(ICB) model shows potential in characterizing imbibition rates in different pores during wettability alteration, the existing ICB models neglect the influence of wettability and viscosity ratio on the imbibition behavior, making it difficult to accurately describe the oil-water imbibition behavior within the porous media. In this work,a new ICB mathematical model is established by introducing pressure balance without assuming the position of the leading front to comprehensively describe the imbibition behavior in a porous medium under different conditions, including gas-liquid spontaneous imbibition and oil-water imbibition.When the pore size distribution of a tight rock is known, this new model can predict the changes of water saturation during the displacement process in the tight rock, and also determine the imbibition rate in pores of different sizes. The water saturation profiles obtained from the new model are validated against the waterflooding simulation results from the CMG, while the imbibition rates calculated by the model are validated against the experimental observations of gas-liquid spontaneous imbibition. The good match above indicates the newly proposed model can show the water saturation profile at a macroscopic scale while capture the underlying physics of the multiphase flow in a porous medium at a microscopic scale. Simulation results obtained from this model indicate that both wettability and viscosity ratio can affect the sequence of fluid imbibition into pores of different sizes during the multiphase flow, where less-viscous wetting fluid is preferentially imbibed into larger pores while more-viscous wetting fluid tends to be imbibed into smaller pores. Furthermore, this model provides an avenue to calculate the imbibition rate in pores of different sizes during wettability alteration and capture the non-Darcy effect in micro-and nano-scale pores.
基金Supported by National Natural Science Foundation of China(52104049)Young Elite Scientist Sponsorship Program by BAST(BYESS2023262)Science Foundation of China University of Petroleum,Beijing(2462022BJRC004).
文摘Considering the phase behaviors in condensate gas reservoirs and the oil-gas two-phase linear flow and boundary-dominated flow in the reservoir,a method for predicting the relationship between oil saturation and pressure in the full-path of tight condensate gas well is proposed,and a model for predicting the transient production from tight condensate gas wells with multiphase flow is established.The research indicates that the relationship curve between condensate oil saturation and pressure is crucial for calculating the pseudo-pressure.In the early stage of production or in areas far from the wellbore with high reservoir pressure,the condensate oil saturation can be calculated using early-stage production dynamic data through material balance models.In the late stage of production or in areas close to the wellbore with low reservoir pressure,the condensate oil saturation can be calculated using the data of constant composition expansion test.In the middle stages of production or when reservoir pressure is at an intermediate level,the data obtained from the previous two stages can be interpolated to form a complete full-path relationship curve between oil saturation and pressure.Through simulation and field application,the new method is verified to be reliable and practical.It can be applied for prediction of middle-stage and late-stage production of tight condensate gas wells and assessment of single-well recoverable reserves.
基金funded by the National Natural Science Foundation of China(Nos.51874215 and 52204351)the China Postdoctoral Science Foundation(2022M722487).
文摘A three-dimensional mathematical model has been established for a novel metallurgy process coupling an annular gas curtain with swirling flow at tundish upper nozzle. The discrete phase model and volume of fluid model were applied to simulate the gas–liquid multiphase flow behavior in tundish and nozzle. The effect of argon flow rate on the migration behavior of bubbles and interface behavior between steel and slag was also investigated. The presented results indicate that the novel coupling process can significantly change the flow pattern in the stream zone of a tundish, prolong the average residence time of liquid steel, and reduce the dead fraction. A complete annular gas curtain is formed around the stopper rod of tundish. Under the action of drag force of liquid steel, a part of small bubbles enter the nozzle through the swirling grooves and gather toward the center of the nozzle by centripetal force. As the argon flow rate increases, the volume fraction of argon gas entering the nozzle increases, which enhances the swirl intensity and increases the concentration of bubbles in the nozzle. To avoid the formation of slag open eye in tundish, the argon flow rate should not exceed 8 L min−1.
基金Project(07JJ4016) supported by the Natural Science Foundation of Hunan Procvince,China
文摘In order to check the validity of the mathematical model for analyzing the flow field in the air-agitated seed precipitation tank,a scaled down experimental apparatus was designed and the colored tracer and KCl tracer were added in the apparatus to follow the real flow line.Virtue tracers were considered in the mathematical model and the algorithm of tracers was built.The comparison of the results between the experiment and numerical calculation shows that the time of the tracer flows out of stirring tube are 40 s in the experiment and 42 s in numerical calculated result.The transient diffusion process and the solution residence time of the numerical calculation are in good agreement with the experimental results,which indicates that the mathematical model is reliable and can be used to predict the flow field of the air-agitated seed precipitation tank.
基金supported by the National Natural Science Foundation of China(Grant Nos.U23B6009 and 12272050).
文摘This review summarizes recent progress in the study of impinging-jet dynamics and atomization,with a focus on liquid sheet formation,instability mechanisms,and the influence of key parameters such as fluid properties,Weber number,and Reynolds number.Special attention is given to atomization behaviors under high pressure and external perturbations.Representative experimental and numerical approaches are introduced,and critical findings under complex conditions are highlighted.In addition,practical applications of impinging-jet technology in aerospace propulsion,biomedical devices,and energy science are discussed.This review aims to serve as a concise reference for researchers interested in multiphase flow dynamics and engineering applications of impinging jets.
基金supported by the National Natural Science Foundation of China(Grant No.52171261).
文摘A floating horizontal-axis tidal current turbine(HATT)is an underwater power generation device where cavitation inevitably occurs on blade surfaces,severely affecting a turbine’s lifespan.Under wave action,these floating turbines exhibit six degrees of freedom motion,potentially intensifying the cavitation on the blade surfaces.This study selects three types of oscillatory motions from the six degrees of freedom:roll,yaw,and pitch.Computational fluid dynamics(CFD)methods are used for numerical calculations,and transient simulations of multiphase flow are conducted on the basis of the Reynolds-Averaged Navier-Stokes(RANS)model.Research has revealed strong correlations between flow velocity,the blade tip speed ratio,and cavitation.During oscillatory motion,the motion period and amplitude also significantly impact cavitation.In roll motion,the cavitation rate can increase by up to 59%with decreasing period,whereas in pitch and yaw motions,the increases are 7.57 times and 36%larger,respectively.With an increase in amplitude during roll motion,the cavitation rate can increase by up to 1.08 times,whereas in pitch and yaw motions,the increases are 3.49 times and 45%,respectively.The cavitation rate on the blade surfaces is the highest in pitch motion,followed by roll and yaw motions.
基金supported by the National Natural Science Foundation of China(Nos.42472332,42102318 and 42006143)the Open Research Fund Program of Zhoushan Field Scientific Observation and Research Station for Marine Geo-Hazards,China Geological Survey(No.ZSORS22-07)+1 种基金the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning(No.TP2019037)the Open Research Fund Program of Marine Ecological Restoration and Smart Ocean Engineering Research Center of Hebei Province(No.HB MESO2312)。
文摘Submarine landslides frequently occur on continental margins and slopes,thereby causing serious damage to offshore structures.Therefore,analyzing their motion behavior and predicting their impact forces are crucial.In this work,the smooth particle hydrodynamics(SPH)algorithm is used in the development of a multiphase flow model for submarine landslides.The underwater landslide and the ambient water are simulated using the non-Newtonian and Newtonian fluid models,respectively.An artificial diffusion term of density is incorporated in the governing equation,and the equation of state is modified to improve the stability and accuracy of the SPH model.Three benchmark problems are simulated using the SPH model.The effect of SPH particle size on the simulated results is also explored.The effects of the rheological parameters on the landslide motion behavior are investigated by conducting a sensitivity analysis.Numerical results fit the experimental data well,indicating the good stability of the SPH model and its accuracy in simulating the motion and impact behavior of submarine landslides.
基金supported by the Postdoctoral Fellow-ship Program of CPSF(Grant No.GZC20233105)the Science Foundation of China University of Petroleum,Beijing(Grant No.2462024XKBH006)+2 种基金the China Postdoctoral Science Foundation(Grant No.2024M753615)the Major Scientific Research Instrument Development Program of National Natural Science Foundation of China(Grant No.52227804)the Youth Science Foundation Program of National Natural Science Foundation of China(Grant No.52404012).
文摘The gas kick represents a major risk in deepwater oil and gas exploration.Understanding the dynamics of gas kick evolution and the associated pressure response characteristics is critical for effective well control.In this paper,we introduce a transient wellbore multiphase flow model specifically developed to simulate gas kick in deepwater dual-gradient drilling,incorporating a downhole separator.The model accounts for the variable mass flow within the annulus and heat exchange between the annular fluid and the formation.Using this model,we analyzed the multiphase flow and thermodynamic behavior during the gas kick.Simulation results reveal a progressive increase in bottom-hole temperature,underscoring its potential as a key indicator for gas kick early detection.Additionally,variable gradient parameters affect not only the annular equivalent circulating density(ECD)profile but also the evolution of the gas kick.The inclusion of a downhole separator alters the annular ECD profile,creating a“broken line”shape,which enhances adaptability to the multi-pressure systems typically encountered in deepwater forma-tion.By adjusting factors such as hollow sphere concentration,separator position,and separation effi-ciency,the annular ECD profile can be effectively customized.This study provides important theoretical insights and practical applications for utilizing dual-gradient drilling technology to address challenges in deepwater formation drilling.
基金the Natural Science Foundation of Shandong Province,China(No.ZR2021QE157).
文摘High-pressure water jet technology has emerged as a highly effective method for removing industrial-scale deposits from pipelines,offering a clean,efficient,and environmentally sustainable alternative to conventional mechanical or chemical cleaning techniques.Among the many parameters influencing its performance,the geometry of the nozzle plays a decisive role in governing jet coherence,impact pressure distribution,and overall cleaning efficiency.In this study,a comprehensive numerical and experimental investigation is conducted to elucidate the influence of nozzle geometry on the behavior of high-pressure water jets.Using Computational Fluid Dynamics(CFD)simulations based on the Volume of Fluid(VOF)approach,the jet dynamics and impingement characteristics of three representative nozzle configurations—flat,conical,and tapered—are systematically analyzed.Particular attention is devoted to the tapered nozzle,where variations in the outlet diameter are explored to determine their effect on flow structure,jet stability,and impact performance.The numerical predictions are rigorously validated against experimental measurements,demonstrating excellent quantitative agreement and confirming the robustness of the computational model.Results show that the tapered nozzle,characterized by its elongated conical transition section,promotes a more stable jet core and superior efflux performance compared to flat and conical geometries.Furthermore,the exit diameter is found to exert a profound influence on jet development.At an inlet pressure of 130 MPa,increasing the tapered nozzle's outlet diameter from 0.8 mm to 1.2 mm enlarges the coherent core region,enhances jet stability,and improves hydraulic energy utilization.Under these conditions,the total impact pressure on the target surface increases by 33.14%,while the overall cleaning efficiency improves by 40.44%.
基金supported by National Natural Science Foundation of China Excellence Research Group Program for“Multiscale Problems in Nonlinear Mechanics”(Grant No.12588201)the National Natural Science Foundation of China(Grant No.12402321)+3 种基金the National Key R&D Program of China(Grant No.2021YFA0716201)the New Cornerstone Science Foundation through the New Cornerstone Investigator Program and the XPLORER PRIZEthe Postdoctoral Fellowship Program of the China Postdoctoral Science Foundation(Grant Nos.GZB20240366 and 2024M751637)Shuimu Tsinghua Scholar Program(Grant No.2023SM038).
文摘Icing of water droplets is a ubiquitous phenomenon with significant implications across natural systems and industrial applications.Despite extensive research,the intricate interplay among heat transfer,mass transport,and phase change during droplet freezing remains incompletely understood,particularly in the context of multiscale dynamics and environmental dependencies.This review critically examines recent advances in uncovering the fundamental mechanisms of droplet icing through experimental,theoretical,and computational approaches.We begin by revisiting the classical tip singularity problem in the freezing of pure water droplets,analyzing its mathematical formulation and physical significance.Subsequent sections explore how environmental boundary conditions and multicomponent effects influence freezing kinetics,solute redistribution,and ice morphology.Furthermore,we evaluate emerging hybrid numerical frameworks that resolve coupled multiphase physics during solidification processes.Finally,we identify key challenges and open questions that require further investigation in this field.
