Water Flow In Channel Research Articles

A well-balanced and positivity-preserving SPH method for shallow water flows in open channels

A well-balanced and positivity-preserving meshless method based on smoothed particle hydrodynamics (SPH) is developed to simulate one-dimensional (1D) and two-dimensional (2D) shallow water (SW) flows in open channels with irregular geometries. A new form of the characteristic equations that govern the water-surface level and water velocity is introduced to specify the numerical inflow/outflow boundary conditions. An additional condition, derived from temporal discretization to determine the time-step size, forces the water depth to be positive. A 1D finite volume shallow water (FVSW) model based on the first-order Godunov upwind method is built to conduct a comparison of the 1D meshless-based and mesh-based SW models. Six benchmark cases – still water, single trapezoidal and rectangular and prismatic and non-prismatic channels, and a dendritic channel network – are employed to validate the proposed models and compared with the exact and mesh-based numerical solutions. A real-world case of the Chicago Area Waterways System (CAWS) is investigated to highlight the performance of the proposed 1D model for a practical hydraulic system.

On the Influences of Air Bubbles on Water Flow in a Two-Dimensional Channel

As an inevitable trend for the sustainable development of the global economy, saving energy and reducing emissions are key goals for the entire world. The use of air bubbles to reduce viscous friction is one of the most effective approaches to achieve this goal, as it may significantly reduce the frictional drag of ships. However, the injection of air bubbles will change flow characteristics near the wall due to the significant differences in density and viscosity between air and water. In addition, parameters such as bubble size, bubble surface tension, bubble number and bubble position also affect the flow near the wall, resulting in significant diversity and instability in two-phase flow. To clarify the mechanism of these effects, a two-dimensional channel flow with air bubbles is studied using Computational Fluid Dynamics (CFD). The interactions between bubbles and water and between bubbles and wall are studied, and the detailed characteristics of bubbles moving in fully developed flow are considered. This study shows that the velocity gradient is the main factor influencing wall shear stress, and the presence of bubbles has a marked impact on the local velocity gradient distribution of the nearby flow. It is also found that shorter distance between a bubble and the wall enhances the flow interaction and leads to more significant perturbations of wall shear stress.

Effect of Pore Shape and Spacing on Water Droplet Dynamics in Flow Channels of Proton Exchange Membrane Fuel Cells

Effective water management increases the performance of proton exchange membrane fuel cells (PEMFCs). The liquid droplet movement mechanism in the cathode channel, the gas-liquid two-phase flow pattern, and the resulting pressure drop are important to water management in PEMFCs. This work employed computational fluid dynamics (CFD) with a volume of fluid (VOF) to simulate the effects of two operating parameters on the liquid water flow in the cathode flow channel: Gas diffusion layer (GDL) pore shape for water emergence, and distance between GDL pores. From seven pore shapes considered in this work, the longer the windward side of the micropore is, the larger the droplet can grow, and the duration of droplet growth movement will be longer. In the cases of two micropores for water introduction, a critical pore distance is noted for whether two droplets coalesce. When the micropore distance was shorter than this critical value, different droplets coalesce after the droplets grew to a certain extent. These results indicate that the pore shape and the distance between pores should be accounted for in future simulations of PEMFC droplet dynamics and that these parameters need to be optimized when designing novel GDL structures.

The Effect of Surface Roughness on Immiscible Displacement Using Pore Scale Simulation

Pore scale immiscible displacement is crucial in oil industry. The surface roughness of throat is an important factor affecting water–oil interface movement. In this paper, the Navier–Stokes (N-S) equation coupled with the phase-field method is adopted to analyze the oil–water flow and interface movement in single channel, considering different surface roughness, diverse wettability and various capillary numbers. The simulation results show that the resistance increases significantly due to the surface roughness. The velocity of interface movement in rough channels is slower than that in smooth channels. The existence of asperities strengthens the interface deformation and promotes the formation of fingering phenomenon. The water flooding process presents different flow patterns in the rough channel with diverse wettability, and the influence of wall roughness on oil–water interface movement is different under various wettability conditions. There is an approximate exponential relationship between the ratio of interface length to channel length and capillary number. When the capillary number exceeds 0.03574, the phenomenon of viscous fingering is obvious, and the influence of capillary number is amplified by roughness.

Капиллярно-волновой варп-двигатель

The generation of surface water flow in channels with sources and resonators of capillary oscillations is detected and investigated. Moving devices with a capillary-wave accelerator of the surface fluid flow are demonstrated. The surface flow of liquid in the channel is generated due to the local deformation of the liquid surface by capillary vibrations and the formation of an excess liquid surface on average near the source and the transport of this surface by waves.

Features of the application of one-dimensional equations of hydrodynamics for free-flow flows

The possibility of applying one-dimensional hydrodynamic equations of a nonstationary flow averaged over the cross-section of the channel during mathematical modeling of long waves-abruptly changing the movement of the water flow in channels is substantiated in the article. The characteristic dimensions of the length are much larger than the depth of the flow-the theory of shallow water. With this averaging, it is necessary to apply some hypotheses, the most important of which is the hypothesis of the distribution of pressure over the depth of the flow

Experimental and numerical study on hydraulic characteristics of multi-level intake for diversion project

Multi-level intake as an inlet of diversions has the advantage of selective withdrawal. To further understand the hydraulic characteristics of this inlet hydraulic structure, experimental model test and numerical simulation were carried out. The results of this study show that the water flow in the diversion channel is stable, and the flow pattern in the lock chamber section is disordered. In addition, the pressure near the entrance of the tunnel is linear, and the water head loss of the upper layer is the largest. Further, the formation of potential vortex flow can be prevented by controlling and scheduling. The results presented in the current work provide new insights into the hydraulics of flow in stratified intake structure and can be used in the design and operation of similar hydraulic projects.

Irrigation sedimentation tanks in the bed of the pumping station inlet channels

The article analyzes the dynamics of channel processes in the irrigation pumping station inlet channels. The field studies of hydraulic and alluvial sediment regimes in the supply channels of pumping stations are analyzed and summarized. The studies of supply channel water flow under conditions of extremely high turbidity of the flow and variability of the morphometric characteristics of the channel are presented. The conditions under which the Saint-Venant equations satisfactorily describe the channel flows in the bed of the supply channels are given. Saint-Venant's twodimensional equations were numerically implemented using an explicit finite-difference scheme. In addition, the results of calculations of the flow field in the supply channels are presented. According to the results of numerical studies, the width of the sedimentation tank was taken to be equal to the design width of the channel, and the speed of water flow in it was 0.25 m/s. The length of the sedimentation tank, ensuring the retention of sediments of the finest fraction (0.05 mm in diameter), was 1042 m. The siltation time of the sedimentation tank can be reduced by 15…20% and amount to about 15 months, considering the unevenness of the velocity distribution diagram in the horizontal plane and the trapezoidal crosssection of the clarifier. Nevertheless, the arrangement of two parallel chambers of the sedimentation tanks makes it possible to be stable for a sufficiently long time.

Laboratory evaluation on temporary plugging performance of degradable preformed particle gels (DPPGs)

In recent years, granular temporary plugging agents (TPA) have been widely studied, especially in repeated fracturing operations, to stimulate oil and gas production in unconventional petroleum reservoirs. They can divert the hydraulic fracturing energy to form more complex fractures that make oil and gas more easily flow into production well. Pre-formed particle gels (PPGs), as deformable particles, are often used in petroleum reservoir water management operations because of their high strength, simple fabrication process, and environmental friendliness. However, their application as TPA is rarely reported. In this paper, degradable PPGs (DPPGs) were employed, and their temporary plugging performance was studied in the laboratory. Bottle tests were first conducted to investigate the swelling and degradation performance. Results show that DPPGs exhibit good swelling ability in an extended range of brine salinity (20000 to 400000 ppm), and DPPGs can be fully degraded, and the degradation time increase with temperature. According to the temporary plugging performance by core flooding experiments, the plugging strength increased with the injection pressure, dry particle size, and swelling ratio (less than 20 times). However, the addition of smaller size particles will prevent large particles from forming deformable blockage on the matrix end surface, and subsequent water flow channels will be easily created, so the plugging performance of the DPPGs will decrease. The above experimental results can provide an experimental and theoretical basis for the application of DPPGs in repeated fracturing operations in unconventional reservoirs.

Water Distribution in Fuel Cell Gas Channels Using a Mechanistic Discrete Particle Model

Water removal and accumulation in fuel cell gas channels is a complex phenomenon which is a consequence of the strength of the capillary forces and inertial forces (1 < Re < 1000). The presence of water in the channel restricts the access of oxygen to diffuse through the gas diffusion layers to the catalyst layer. The air supplied exchanges momentum to the droplets and water clusters, causing detachment when the adhesion force is overcome.Water emerging from discrete locations as droplets interact with both the channel walls and each discrete water cluster, depending on the configuration and operating conditions. Complexity increases as multiple detachment and coalescence events occur over large channel lengths and time scales. Modelling these systems with traditional method computational fluid dynamic (CFD) methods is computationally expensive so we have developed a new mechanistic discrete particle model to handle the liquid water two-phase flow.Taking inspiration from interface resolving volume of fluid (VoF) simulations of water flow in gas channels, we use analytically equations determined by the equilibrium contact angle in different configurations on the channel wall to predict detachment times and coalescence events. We compare the prediction of water area coverage ratio and channel saturation to the VoF simulations and can also estimate dynamic pressure drop.Using this model, we are able to investigate the dynamic effects of liquid water accumulation and distribution in the channel, with often periodic detachment events arising from the formation of liquid plugs. Consequently, the model is able to investigate the effect of the channel wall wettability, from hydrophilic to hydrophobic and the impact that has on the distribution and accumulation of water in the system.We compare the speed of this model against the VoF simulations to show that this type of modelling of two-phase flow in the channel can enable higher resolution accuracy when coupled with continuum scale approaches. Furthermore, with this approach it is possible to investigate the effect of: channel dimensions, liquid water flow rate and spatial location of liquid water emergence. This should allow for designed fuel cell structures to be evaluated. Figure 1

A Well-Balanced and Positivity-Preserving Numerical Model for Shallow Water Flows in Channels with Wet–Dry Fronts

In this paper, a novel well-balanced and positivity-preserving finite-volume method for the shallow water flows in open channels with non-uniform width and irregular bottom topography is developed. Special attentions are paid to guarantee the well-balanced property not only over the fully submerged domain, but also in those partially flooded and dry regions near the wet–dry interfaces. Such property is achieved via a new method involving local surface reconstruction and special discretization of the geometric source terms. The desired properties of the proposed numerical schemes are verified by a number of numerical experiments.

Fast Advective Water Flow Through Nanochannels in Clay Interlayers: Implications for Moisture Transport in Soils and Unconventional Oil/Gas Production

Water flow in nanometer or sub-nanometer hydrophilic channels bears special importance in diverse fields of science and engineering. However, the nature of such water flow remains elusive. Here, we...

Effects of nanopore geometry on confined water flow: A view of lattice Boltzmann simulation

Water flow in nanoscale channel is demonstrated to be affected by the robust water-wall interactions, including that the flow significantly deviates from the conventional continuum flow. As suggested in different results of experimental observation and simulation in recent literature, nanopores exhibit higher/lower-than-expected flow capacity. Most existing studies are limited to simple geometry that displays a circular cross-section. However, the flow dynamics of water in noncircular pores significantly deviates from the Hagen–Poiseuille flow equation adopted in circular pores that exhibit different contact angles and dimensions. In this study, molecular interactions between water and the solid inner wall are substituted into the formulations of the Lattice Boltzmann method to simulate the flow dynamics in nanopores that exhibit different cross-sectional shapes and wettability. The results show that, under identical cross-sectional area injection pressure, the circular nanopore exhibits the maximum flow capacity. In terms of a circular cross-sectional shape, the constant density lines are also circular and concentric. For angular cross-sectional shape, the constant density lines do not comply with the cross-sectional shape, and the density varies significantly at the corner. The effects of geometry and density distribution of different contact angles are elucidated. An empirical formula under different geometry and wettability has been established, which is of high significance in modeling water flow in various engineering nano-systems such as shale matrix, membrane, and aquaporins.

Application of Polymeric microspheres in extra low permeability reservoir in Huabei Oilfield

Aiming at the problems of low water displacement recovery effect in extra low permeability reservoir of Fault-block B10 in Huabei oilfield, the oil recovery technique of surfactant flooding under polymeric microspheres was proposed in this paper. According to the features of polymeric microspheres deep profile control technique, expansion, plugging capacity and migration ability of two samples were evaluated. On the basis of these, a polymeric microspheres matched with the B10 reservoir was selected and tested in the field. Field application indicated that average pressure elevation of each well was up to 4 MPa, corresponding wells efficiency were 88%, comprehensive water was decreased by 6.6% and cumulative incremental oil production was 3350t.Fault block B10 in Huabei Oilfield had an average porosity of 17.6% and an average permeability of 3.5×10−3μm2. It belonged to a low porosity ultra-low permeability reservoir. The surface crude oil viscosity was 90mPa.s, which belonged to ordinary heavy oil reservoir. Many years of water injection had formed a fixed water flow channel in the formation. The water injection wave and volume were not balanced, and the problem of inefficient or ineffective water injection circulation was becoming more and more prominent. At present, the comprehensive water cut had reached 90%. After surfactant flooding in some well groups, due to the serious heterogeneity of reservoir, displacement fingering was obvious and the implementation effect was poor. As a new type of deep profile control and flooding agent, polymer microspheres can form step-by-step plugging after entering the low-permeability reservoir, and greatly adjust the water flooding flow field and expand the sweep volume [1]. In order to explore the adaptability of polymer microsphere to B10 reservoir, a polymer microsphere suitable for B10 reservoir was selected by static expansion of microsphere and dynamic physical model plugging experiment of core. Field application showed that the polymer microsphere had good adaptability in B10 fault block.

Application of SVM, ANN, GRNN, RF, GP and RT models for predicting discharge coefficients of oblique sluice gates using experimental data

AbstractGates are commonly used to adjust water flow in open channels. By using an oblique/inclined gate, the water transferring capacity of open irrigation canals can be increased. Investigation of free and submerged discharge coefficients for inclined sluice gates is the focus of the present study. First an experimental apparatus incorporating an inclined gate was created. The inclined angle (β) and gate opening (a) were experiment variables, and the five inclination angles include: 0° (vertical gate), 15°, 30°, 45° and 60°. Experimental results showed a greater convergence of flow lines under the gate and increasing the gate angle causes the discharge coefficient to increase. Also experiments showed that increasing the submergence rate (yt/a), decreases the inclined gate discharge coefficient. Performance metrics were created for the experimental results. The metrics utilized Gaussian process (GP) regression, support vector machine (SVM), artificial neural networks (ANN), generalized regression neural network (GRNN), random forest (RF) regression and random tree (RT) based models which were used to predict discharge coefficients (Cd) in both submerged and free flow conditions. The model input parameters were the ratio of the upstream water depth to gate opening (y/a) and the inclined angle (β) for free flow and also the submergence rate (yt/a) for submerged flow. The prediction models show that the ANN model in free flow conditions has the following performance metrics: Coefficient of determination, R2= 0.9957, Root Mean Square Error (RMSE) = 0.0044, and Mean Absolute Error (MAE) = 0.0017. The performance metrics for submerged flow conditions were R2 = 0.9922, RMSE = 0.0079 and MAE = 0.0054. The ANN approach is the most accurate model compared to the others.

A steady-state-preserving scheme for shallow water flows in channels

A steady-state-preserving numerical model is developed for the shallow water equations in channels in the current study. The proposed numerical model is based on the finite volume method and capable to preserve both the moving-water and still-water steady states. In order to preserve the general steady states, the source terms in the momentum equation are incorporated into a global flux term; and the new momentum equation with global flux term is then relaxed in order to avoid the non-linearity in the computation. One can thus develop an upwind/modified-HLL hybrid Riemann solver to estimate the fluxes in different flow regimes. The developed numerical model can preserve the general steady states, and one avoids: (1) non-trivial root-finding for point values of wetted cross-sectional area A at cell interfaces; (2) complex discretization of geometric source terms incorporating artificial conservation corrections. The developed numerical model has second order accuracy in both space and time. Numerical solutions are presented to demonstrate that the proposed numerical model is capable to exactly preserve both moving-water and still-water steady states.

Study and Characterization of Pump Control System Tools in Mini Open Channel Water Flow Simulator

This study aims to study the characterization of the pump control system in a mini open channel water flow simulator. This pump control system aims to facilitate operators in controlling pumps based on the Internet of Thing (IoT). The sample in this study focuses on red objects, where the sample can be monitored through a recording device that has been provided, and can be made in the form of realtime graphics. The results showed that in the simulator trial, the pump control system and the recording device were in the good category. After repairs are made, the development results are in the very good category, because they produce accurate results on the pump control system. Thus, the pump control system can be used and developed for large-scale canal water flow.

Numerical investigation of water dynamics in a novel wettability gradient anode flow channel for proton exchange membrane fuel cells

The effective removal and transport of water in flow channels play an important role in the water management of proton exchange membrane fuel cells (PEMFCs). In this paper, a novel design of anode serpentine flow channel with the wettability gradient wall is discussed and numerically investigated by utilizing the volume-of-fluid (VOF) method. The effects of the contact angle and the wettability gradient of channel walls, as well as hydrogen flow velocity and water droplet size, on the droplet dynamic behavior are studied. The results indicate that compared with the conventional flow channel, the water droplet can be more effectively removed from the turning part in the wettability gradient flow channel. And the water removal ability in the turning part is improved with the increase of the wettability gradient. Moreover, the wettability gradient flow channel can also improve the water removal performance for the cases with different hydrogen flow velocities and water droplet sizes. This study provides ideas for guiding the design of flow channel to effectively enhance anode water management.

Insight to peroxone-Fe(III) joint conditioning-horizontal electro-dewatering process on water reduction in activated sludge: Performance and mechanisms

Peroxone disintegration–Fe(III) coagulation (peroxone–Fe(III)) joint conditioning was proposed to enhance the horizontal electro-dewatering (HED) effect of activated sludge (AS). Operating parameters were optimized and the evolutions of AS physicochemical properties, water fractions distribution, organic matter, extracellular polymeric substance (EPS) key components, functional groups, and protein secondary structures during the process were identified. Under the optimized joint conditioning parameters, dewatered AS achieved a final water content of 84.88 ± 0.17% and its bound water content (BWC) was decreased by 1.88 ± 0.28 g/g dry solid. During peroxone pretreatment, the yielded HO decreased the AS floc size, disintegrated the EPS network structure and cell wall, released the bound water, and extracted proteins, polysaccharides, and humic acid-like materials. Furthermore, soluble microbial byproduct-like materials (SMBP) in the EPS layers and tyrosine in tightly bound EPS significantly increased. Protein structures were destroyed, decreasing their water affinity. Subsequent Fe(III) addition re-coagulated broken flocs fragments and EPS fractions, built water flow channels, removed tyrosine and SMBP, and reduced α-helix percentage in slime, facilitating AS dewatering. After joint conditioning, the bound water and intracellular substances were further released by HED. Therefore, the peroxone–Fe(III)–HED process exhibited an excellent performance in AS water reduction.

Water flow motion in the vehicle of main channels

The article considers a numerical study of the movement of water flow in the Amu-Bukhara Machine Channel (ABMCh-Bukhara region). Water intake to the inlet channel is carried out from one of the most muddy rivers in Central Asia in a damless manner, therefore, ensuring the flow of clarified water into the anterior chambers of pumping stations is an urgent task. A numerical study is a study of the hydrodynamic parameters of the flow and, based on the data obtained, the developed recommendation is the aim of this work. The determination of the main hydraulic parameters of the flow moving in the riverbed by numerical research is accepted as a research method. According to the developed model, consisting of hydrodynamic equations, based on the law of conservation of momentum and mass, data on the dynamics of velocities of the ABMCh supply channel are obtained and zones of uneven flow in the channel are determined. A recommendation has been developed that allows quasi-uniform movement, which helps to prevent the formation of deformation of the supply channel of the pumping station and the entry of suspended and bottom sediments into the chamber of the pumping station.