Water Transport Processes Research Articles

Transport behavior of water and ions through positively charged nanopores

• Investigating the application of charge-modified nanopores in water-ion separation. • Studying the effect of positively charged nanopore on water permeability. • Unveiling the complex interactions between charge-modified nanopore and hydration ions. Two-dimensional nanoporous membranes are promising materials for seawater desalination. However, the effect of nanopore charge properties on desalination performance, especially on water permeability, has not yet been systematically investigated. In this work, molecular dynamics simulations were carried out to elucidate the impact of nanopore charge modification (variated from 0 to 1.0e) on water permeability and ions conduction. The highest water permeability was observed when the modification was approximately 0.25e. The nanopore charge conditions significantly impacted water dynamic behaviors, leading to the transition of water transport processes from continuum state to non-continuum state with the increase of nanopore charge. In addition, we found that the positively charged nanopores not only effectively impede cation permeation, but also strongly impact the diffusion behavior of anions. This work unveils in-depth insights into the mechanism of saline water transport through the charge-modified nanopores and highlights the importance of the nanopore charge states for desalination. Meanwhile, it provides useful guidelines for the rational design of optimal nanoporous membranes in the future.

Simulation of water and salt transport in the Kaidu River Irrigation District using the modified SWAT-Salt

Soil salinization is the major factor affecting the sustainable development of agriculture in the Kaidu River Irrigation District (KRID) in Xinjiang Province, China. To better understand water and salt variation regularity in the KRID, this study established a watershed-scale distributed water and salt transport model for the KRID based on the new Soil and Water Assessment Tool with a salinity module (SWAT-Salt). Its point source salt module and irrigation water salt module were modified in the study to obtain more accurate simulation results. Based on evaluation indices, the simulation results of streamflow, salt loading, and crop yield showed that the modified model can more accurately depict water and salt transport processes in the KRID and has good applicability. According to the simulation results, the average annual amount of water and salt entering Bosten Lake through the drainage canal accounted for 15 % and 51 %, reaching 4.29 × 108 m3 and 57.87 × 104 t respectively. The drainage and salt discharge during winter irrigation accounted for 69 % and 74 %, reaching 2.95 × 108 m3 and 42.47 × 104 t, respectively. However, the regions along Bosten Lake had high groundwater and soil salinity, facing a risk of increased salinization and necessitating land or water management to decrease salinization. In conclusion, the modified SWAT-Salt can be applied in agricultural irrigation areas with more diverse irrigation sources and is a useful tool for investigating and assessing watershed-scale salinization, as well as implementing targeted management strategies to reduce salinization.

A Wet/Dry Point Treatment Method of FVCOM, Part II: Application to the Okatee/Colleton River in South Carolina

The wet/dry point treatment method of FVCOM was applied to simulate the tide-induced flooding/drying process in the estuarine–tidal-creek–saltmarsh complex of the Okatee/Colleton River Estuary, South Carolina. The simulation results were compared with observed currents at three mooring sites and flooded areas observed from remote-sensing hypsometric measurements, demonstrating that FVCOM can robustly reproduce tidal and residual currents in the river and the flooding process onto the intertidal saltmarsh. The simulated flow field reveals that the Okatee/Colleton River Estuary is characterized by multiple residual eddies. Driven by the periodic tidal forcing, this estuarine system features a chaotic water transport process. Numerous residual eddies around the barrier complex in the Colleton River likely enhance the water exchange between the Okatee/Colleton River Estuary and the outer Broad River. A sensitivity study of flooding speed to the slope of the inter-tidal zone suggests that the saltmarsh bathymetry considerably influences the water elevation near low slack water but not on the maximum water coverage area at high slack water.

Root Water Uptake Patterns for Nitraria during the Growth Period Differing in Time Interval from a Precipitation Event in Arid Regions

Vegetation root water uptake is one of the most central water transport processes along the soil-vegetation-atmosphere interface particularly in (semi-)arid ecosystems. The identification and quantification of root activities and water uptake patterns of arid vegetation remain challenging. This paper aims at the quantitative examination of water uptake behaviors of Nitraria, a prevalent desert species in arid environments, during the growth phase via a multivariate linear mixed model based on water stable isotopes, with a main focus on the time interval from a precipitation pulse. The observations indicate that the precipitation events exert periodic significant pulse-effects on vegetation water uptake through direct absorption (contribution of almost 75%) and activation of deep root activity at a certain depth. While in most occasions without rainfall, Nitraria relies on its extremely extensive shallow roots in surface-near lateral zone (contribution of about 60%) to extract massive soil as well as the hydraulic lifting mechanism to survive drought. Achievements would be beneficial to enhancing the understanding of entangled water transport processes and eco-hydrological feedbacks along soil-vegetation interface in arid ecosystems and contribute to a scientific allocation to water resources with the consideration of ecological protection.

A quantitative study of salinity effect on water diffusion in n-alkane phases: From pore-scale experiments to molecular dynamic simulation

Numerous mechanisms have been proposed to untangle the effect of a low concentration of dissolved salts in the water flooding medium. One potential mechanism for enhanced oil movement is proposed with osmosis effect, however, the process of water transport through the oil phase, due to a salinity contrast, is not fully understood. In our study, we used three aqueous solutions and two alkanes in a series of microfluidic experiments with hydrophobically coated glass micro-chips for mimicking the low-salinity waterflooding process in an oil-wet rock formation. We created multiple systems of low-salinity water-alkane/high-salinity water in the porous micromodel, and afterward, continuously monitored the domain for 70 h. We noted that ionic strength and the hydrocarbon chain length both played important roles in water diffusion. A salinity contrast of 1.7 g/L-170 g/L caused a higher water volumetric flux than 50 g/L-170 g/L for both alkanes. The difference in water volumetric fluxes for those two contrasts were not proportional to the salinity contrast during the experimental period. There was no simple relationship between the chain length of hydrocarbon and water volumetric flux. Moreover, to investigate the effect of salinity on water behavior in heptane, we conducted molecular dynamic (MD) simulations by considering three different concentrations in the high-salinity water region featuring our experiments. The results indicated that high salinity limited the water diffusion from high-salinity phase into the oil phase and reduced the possibility of water entering the heptane phase. Therefore, the net flux of water from the pure water side to the salty waterside was enhanced.

Effect of In-Pore Wettability on Mass Transfer Performance of Fuel Cell Gas Diffusion Layer

The gas diffusion layer (GDL), as the main mass transfer carrier in a hydrogen fuel cell, transports fuel and discharges water, the only by-product of the electrochemical reaction. The dispersion process of water in the pore will hinder the diffusion of gas, thus reducing the concentration of fuel gas at the catalytic site, resulting in the decrease of the electrochemical reaction rate. In this paper, the effect of wettability in the GDL hole on the water transport process is studied. When the pore wall is hydrophilic, the liquid phase is affected by the gas phase eddy current velocity field, and the particles at the center advance to the edge, forming a liquid phase interface with a thin center and thick edge. With the increase of the wall contact angle, the curvature of the three-phase interface increases, the wall adhesion decreases, and the liquid phase is more likely to be discharged. When the contact angle is 130°, the liquid phase almost does not shift in the hole with a radius of 5 μm. With the increase of the radius or inlet pressure difference, the liquid phase is discharged gradually, and the discharge rate of the liquid phase is only related to the wettability of the wall.

Influence of Gate Dams on Yellow River Delta Wetlands

Nested Delft 3D and Hydrus 1D models were applied to simulate variations in the hydrological process of tidal creeks, soil water, and salt transport in the soil profile of the reconstruction area in the Yellow River Delta under six gate dam scenarios. The results showed that the gate dam set up near the sea area was more conducive to reducing the variation range of water depth in the reconstruction area. The water depth changes in scenarios with 6 m gate valves were higher than those with 3 m sluice valves in the same gate dam location. The variations in surface water salinity, cumulative flooding time, flooding frequency, and cumulative infiltration in each scenario were similar to those for water depth. Rapid changes in soil water and salt content occurred in each scenario in periods without flooding. The fluctuation of soil salt content in different soil layers was contrary to the changes in soil water content. The overall difference in the soil salt contents and soil water content of the soil profile in scenarios with a gate dam near the sea was relatively larger than that of those with a gate dam near the shore. Obvious differences in both the soil water content and soil salt content between scenarios with 3 m and 6 m gate valves were not observed. Our results contribute to the understanding of the function of gate dams in controlling soil water and salt content in coastal wetlands.

Quantitative Stable Isotope Tracing of Water Uptake in Cynanchum sibiricum during Its Growth Period in Arid Areas of Northwest China

Vegetation root water uptake plays a significant role in water transport processes and has multiple effects along the soil–vegetation–atmosphere interface, particularly in semi-arid and arid ecosystems. The objective of this study was to quantitatively examine the water uptake in Cynanchum sibiricum, a common desert rattan plant in arid regions, during its growth period, as well as to assess the relevance of the contributions of various water sources via a multivariate linear mixed model based on water-stable isotopes and eliminating the significant short-term impact of precipitation pulses on root water uptake. The results indicated that when the influence of a precipitation event was minimized, 0–10 cm soil water was the dominant water source for Cynanchum sibiricum in its growth phase, and that the species’ relative uptake of rainfall was positively proportional to that of 10–70 cm soil water while negatively proportional to that of 0–10 cm soil water. We concluded that Cynanchum sibiricum relies on its active roots extending transversely to extract water from shallow soil to survive under extreme drought conditions and would be inseparable from the symbiosis formed with other deep-rooted vegetation. Additional research into disentangling the water transport processes and studying the ecohydrological feedback along the soil–vegetation interface in arid ecosystems would be beneficial and could contribute to the evidence-based management of water resources for ecological protection.

Droplet motion on superhydrophobic/superhydrophilic wedge-shaped patterned surfaces with different micro-morphologies

Superhydrophobic/superhydrophilic wedge-shaped patterned surface (SSWPS) has promising application prospects in water transportation, fog harvesting, etc., and has therefore been widely prepared and studied. However, influences of micro-morphologies of the SSWPS on water transportation and fog harvesting, which may be of great significance, have rarely been reported. Here, we firstly investigated the influences of the micro-morphologies on the water transportation and fog harvesting processes. SSWPSs with different microgrooves were prepared by laser processing, and the influence mechanisms of the micro-morphologies on droplet motion behaviors were then investigated. The different micro-morphologies contributed to dissimilar capillary forces and fluid resistances during the transportation process, thus resulting in the different transport speeds and fog harvesting efficiencies. For regular microgrooves with 0° direction and larger depths, the capillary forces were relatively larger while the fluid resistances were smaller, which led to the faster water transport speeds of the SSWPS. Fog harvesting experiments on different surfaces demonstrated that the SSWPS with faster water transport speed exhibited much higher fog harvesting efficiency, and could achieve long-time continuous harvesting, which was expected to facilitate application of the SSWPS.

Hydraulic-driven piezo-activation of peroxymonosulfate for carbamazepine degradation with ultralow energy consumption

Although peroxymonosulfate (PMS) coupling with ultrasonic piezo-catalysis (PE) or electrolysis (E) exhibited satisfactory efficiency of organics degradation by generating more reactive species, the relatively high energy consumption restricted their application. Hydro-energy, as a clean energy resource, is available in water treatment and transportation processes. Herein, a hydraulic-driven PE-PMS process was proposed, using barium titanate as piezoelectric material for carbamazepine (CBZ) degradation. Results showed that CBZ was efficiently degraded (76.17%, 180 min) in the PE-PMS process with a pseudo-first-order rate constant of 8.15 × 10−3 min−1. Moreover, the degradation ratio of CBZ was still up to 64.19% after 10 cycles without valence and crystal phase changes. Importantly, the energy consumption of the hydraulic PE-PMS process (428.65 kWh m−3 order−1) was only 2.56% and 22.87% of ultrasonic PE-PMS and traditional E-PMS processes, respectively. Finite element method and electrochemical measurement were performed to understand the influence of the hydraulic gradient (G). A positive correlation between G and piezo-potential/current was found in the hydraulic PE-PMS process. However, there was an optimal G value (7.72 s−1) for CBZ degradation. Further studies showed that ·OH played a major role in CBZ degradation during the hydraulic PE-PMS process. Various refractory organics could be effectively degraded in this process, while a satisfactory degradation of CBZ was observed in the actual water matrices. Therefore, the hydraulic-driven PE-PMS system might be an efficient, sustainable, and energy-saving process for water treatment by the potential utilization of residual hydro-energy in water transportation.

Cover crops effects on soil hydraulic properties in two contrasting Mollisols of the Argentinean Pampas region

AbstractDecreasing physical quality of Mollisols in the Argentinean Pampas region is observed due to simplified crop rotations. The main objective of this work was to evaluate the effects of cover cropping management on soil water capture, transport, and storage as compared with different crop rotations with bare fallow in two different and representative Mollisols of the Argentinean Pampas region (one Typic Argiudoll [TA] and one Typic Hapludoll [TH]). Water capture, transport, and storage processes were assessed through soil sorptivity, infiltration tests at different pressures heads, and soil water retention curve determination. In addition, aggregate stability and soil organic carbon (SOC) were determined and the relationship between studied variables and processes was evaluated. It was observed that soybean [Glycine max (L.) Merr.] monocultures jeopardize Mollisols conservation, decreasing water capture and transport and SOC content. The inclusion of cover cropping management increased the soil water transport in the TA and water capture in the TH, as compared with bare fallow rotations. In this sense, our results show that cover cropping could be a suitable management in order to recover degraded soils due to simplified crop rotations in Mollisols from the Argentina Pampas region.

Effect of afforestation on soil water dynamics and water uptake under different rainfall types on the Loess hillslope

Knowledge on water uptake is crucial for understanding water transport processes of the soil–vegetation-atmosphere continuum and plant survival strategy in the Loess Plateau. Even though vegetation water sources have been widely explored using hydrogen and oxygen isotopes, the quantification of vegetation water sources after returning farmland to forestland/grassland under different rainfall types, especially extreme rainstorm event, still remains challenging due to difficulties in field monitoring. This study collected precipitation, soil water from 0 to 100 cm soil layer and xylem/stem water and measured their hydrogen (δD) and oxygen (δ18O) isotope compositions in Robinia pseudoacacia forestland (PL), natural forestland (NF) and natural grassland (NG) under four typical rainfall events. The results indicated that among three vegetation types, soil water content was lowest in PL during each rainfall event. In addition, the sensitivity of water-use strategies to precipitation was affected by rainfall types, dry/wet periods and vegetation types. When antecedent soil water was deficit, vegetation water use was more sensitive to precipitation, and the primary water sources after rainfall transferred from deep soil to upper soil. However, when the antecedent soil water was sufficient, water uptake after rainfall tended to be more homogeneous in different soil layers. Among three vegetation types, Robinia pseudoacacia was more sensitive to precipitation. During the extreme rainstorm event II, in PL, the primary water source shifted from the 80–100 cm soil water before rainfall (88.7%) to the 0–10 cm soil water at 1 day after rainfall (64.3%) and the 0–20 cm soil water at 7 day after rainfall (82.8%). Thus, Robinia pseudoacacia can adapt to the environment by switching water-use strategy. The finding can provide a guidance for vegetation rehabilitation in the Loess Plateau.

Water and ion diffusion in partially-water saturated compacted kaolinite: Role played by vapor-phase diffusion in water mobility

Diffusion is the main transport process of water and solutes in clay-rich porous media owing to their very low permeability, so they are widely used as barriers against contaminant spreading. However, the prediction of contaminant mobility can be very complicated when these media are partially water-saturated. We conducted diffusion experiments for water (HTO and HDO) and ions (22Na+ and 125I−) through partially water saturated compacted kaolinite, a weakly charged clay material, to quantify the distinct diffusive behavior of these species. The osmosis method was used to set kaolinite samples at 67, 86 and 100% saturation. The results showed that desaturation led to a sharp decrease in diffusive rates by factors of 6.5, 18 and 35 for HTO, 125I− and 22Na+, respectively, from 100 to 67% of the degree of saturation. Thus, to interpret water diffusivities, we proposed a model taking into account the diffusion of water in both gas and liquid phases, using diffusion data obtained for ions, considered as inert species. This model was capable of properly predicting water diffusive flux, especially at a low degree of saturation (67% saturation), for which the assumption made for the occurrence of air phase continuity throughout the sample appears to be more relevant than at 86% saturation.

Molecular dynamics study of fluid-fluid and solid-fluid interactions in mixed-wet shale pores

Mixed wet pores are abundant in shales, yet there is little to no information on the behavior of fluids confined within pores characterized by one hydrophilic and one hydrophobic surface. This mixed wettability can impact fluid storage, distribution, capillary pressures and transport. In this study, we use molecular dynamics simulations to describe the initial distribution of reservoir fluids, such as multicomponent hydrocarbon mixtures and water, in mixed-wet pores. This is an essential pre-requisite to additional studies documenting fluid transport in such pores. The molecular model of the mixed wet pore used consists of kerogen separated by some distance from two clay surfaces. We evaluate spatial distribution of water and individual hydrocarbon species, at varying values of water concentration. Throughout the entire study, the results from the equilibrated system indicate a high affinity between the heavy components, such as the asphaltene/resin fraction and the kerogen surfaces. The more surprising result is the hydrogen bonding observed between the polar constituents in the asphaltene/resin fraction and water. This creates a situation where the asphaltene/resin fraction shows an affinity towards water. When this happens, the hydrophilic clay surface effectively becomes hydrophobic. A pore bounded by an asphaltene layer on one side and kerogen on the other is more oil-wetting than mixed-wet. The presence of asphaltenes can therefore expect to create conditions of modified wettability that will impact oil recovery, oil transport and distribution. Another surprising result in this work is that water forms structures that bridge between opposing surfaces of the model. These water bridges are seen to happen for water concentration values larger than 20%. In other words, water is not merely just adsorbed on to the clay surfaces, but also forms these bridge-like structures. Nevertheless, we still observe a strong affinity between the asphaltene/resin fraction and water leading to a lesser degree of mixed wettability. This study is the first, to the best of our knowledge, that considers water and multicomponent hydrocarbon mixtures in mixed-wet pores with realistic surface chemistry and constitutes a necessary first step towards additional studies related to water and hydrocarbon transport and EOR processes in shale nanopores.

X-ray speckle-based dark-field imaging of water transport in porous ceramics

The evaluation of liquid transport through porous ceramics are of high importance in numerous applications of these materials, ranging from chemical and physical filters to biomaterials. We present a proof-of-concept of the capability of speckle-based Xray dark-field imaging (XDFI) for studying the water transport through porous materials with high sensitivity and sub-pixel resolution in a laboratory. Speckle-based imaging (SBI) takes advantage of a simple and flexible setup, with only an additional and inexpensive textured mask, to provide complementary multi-contrast images. Porous ceramic samples with different pore size ranges were imaged in dry and different pure water-saturated states, via an X-ray speckle-tracking setup. The retrieved darkfield images revealed a high sensitivity to (1) the pore size range and to (2) the local water saturation degree. Independently of the pore size range, the dark-field signal decreased upon water saturation. Compared with previously reported laboratory-scale XDFI results for water transport through porous materials, the speckle-tracking approach allows achieving higher temporal and spatial resolutions, thus broadening the range of (water) transport processes which can be investigated without using any contrast agent.

Relationship between water transport behaviour and interlayer voids of 3D printed concrete

3D printed concrete is a rising technology recently developed for construction industry. Unlike conventional concrete, since 3D printed elements are built by using a layer-deposition process, the distinct void generated between the printed concrete filaments considerably reduce mechanical strength and durability of 3D printed concrete. Using X-CT technology combined with CsCl enhancement, this study aims at investigating the water transport characteristics at different interlayer zones of 3D printed concrete, cast concrete as the reference. Meanwhile, the void characteristics of different interlayer zones are analyzed to establish quantitatively the relationship between the void distribution and the water transport process. It can be found that those voids at the interlayer zone led to a faster water transport along the printed concrete’ interlayer zone than that of cast concrete. In addition, the percentages of 0.1 mm-0.6 mm and 1 mm-4 mm voids size are observed to have an opposite effect on the water.

The driving mechanism of cement hydrated products leaching on as-built cement concrete bridge deck pavements

Recently, a new distress type in as-built dense-graded asphalt concrete (DGAC) paved on concrete bridge decks, namely alkali leaching, has been detected in China. The water carries dissolved alkali ions from the cement concrete deck to the pavement surface and reacts with CO2 in the air to form whitish carbonate deposits. The “bottom-up” water transportation process in the presence of the natural environment without vehicle loading effect is a complicated problem. Thereby, scrutiny of the driving force of the “bottom-up” water transportation process in cement concrete bridge deck pavements (CCBDPs) plays a vital role in realizing the mechanism of alkali leaching. In the present study, three potential driving mechanisms that may cause this process are proposed and simulated in the laboratory, including water vapor diffusion under action of multiple temperatures and relative humidity (RH), capillary rise, and leaching water caused by variation of atmospheric pressure. The microstructure of alkali leaching samples cored from distress pavement is also carefully examined by X-ray CT. The obtained results show that the diffusion mass of water vapor demonstrates a rapid lessening with the reduction of the relative humidity differences. A highly linear correlation between the RH difference and the diffusion flux of the water vapor for different temperatures is also identified, indicating that the DGAC with various air voids follows Fick’s first law of diffusion. Further, capillary rise indeed occurs in the DGAC but does not contribute to the alkali leaching process. The pressure difference could continuously drive the leaching water to the surface of DGAC samples, and the critical pressure difference (0.3–0.7 kPa) would be generally less than the daily variation of the atmospheric pressure (approximately 0.8 kPa in weather alternate days). The quantitative analysis of the internal structure for alkali leaching cores also reveals that the distressed cores present relatively higher void ratios, especially for small volume and narrow pores. The entrapped air within unsaturated pores provides the precondition for water transport subjected to the atmospheric pressure differences. These findings contribute to the understanding of static moisture transportation in the dense-graded asphalt mixtures and clarify the main driving mechanism of moisture-induced alkali leaching on CCBDPs.

Superior Unidirectional Water Transport and Mechanically Stable 3D Orthogonal Woven Fabric for Human Body Moisture and Thermal Management.

Unidirectional water transport performance is vital for maintaining human thermal and wet comfort in the field of garment materials. In this work, a 3D orthogonal woven fabric (3DOWF) with excellent one-way transport capacity and mechanical properties is developed via 3D weaving and plasma treatment. The 3DOWF consists of polyester yarns (first layer), cotton yarns (second layer), and viscose yarns (third layer) with successively enhanced water absorption capacity. This allows droplets to penetrate spontaneously from the hydrophobic layer to the hydrophilic layer but not vice versa. Moreover, the Coolmax yarn with the core suction effect in the Z-direction and the plasma-treated polyester of the 3DOWF are shown to efficiently speed up the water transport process. In particular, the water penetration rate of the 3DOWF reaches 25µl s-1 . In turn, the surface temperature after water absorption is increased by 2.6°C compared with the cotton fabric, while the tensile strengths in the weft and warp directions of the 3DOWF are 49.62 and 18MPa, respectively. These values represent the best insulation and mechanical characteristics thus far reported among unidirectional water transport fabrics. Therefore, the 3DOWF has great potential for use in watchbands, backpack belts, insoles, and other functional textiles.

Tree-inspired lignin microrods-based composite heterogeneous nanochannels for ion transport and osmotic energy harvesting

One of the key processes of tree lignification is that lignin penetrates into the cell wall and fills in the cell wall framework, thereby increasing the hardness and hydrophobic of the tree channels, which is beneficial to consolidate and support the tree cell wall and water transport. Inspired by this natural process, we demonstrated a lignin-based nanofluidic heterogeneous membrane that closely mimics the channels in tree, which can realize ion transport function and effectively capture reverse electrodialysis. The membrane was synthesized by heating dealkaline lignin and PVA at 200 °C and this formed fusiform microrods and a closed-packed membrane. Simultaneously, this membrane composited with anodized aluminum (AAO) channels membrane at 200 °C to form asymmetric heterogeneous nanochannels membrane, which can transport counter-ions and harvest osmotic energy. This membrane implements ion current rectification in 0.1 M KCl electrolyte solution at pH 3 due to the confinement of pores and opposite surface charges in lignin-based heterogeneous nanochannel. An output power density of 0.97 W m−2 is obtained under a 50-fold salinity gradient, which can be further improved to 1.19 W m−2 by increasing the salinity gradient from 50-fold to 500-fold. Accordingly, this nanofluidic membranes were prepared by using lignin, the key component in tree, which not only mimicked a crucial process of the water and ionic transport process of channels in tree, but also had the prospect in the field of osmotic energy harvesting.

Lattice Boltzmann method modeling and experimental study on liquid water characteristics in the gas diffusion layer of proton exchange membrane fuel cells

Water transport through the gas diffusion layer (GDL) is vital to proton exchange membrane fuel cells (PEMFCs), especially under flooding conditions. In this paper, a two-dimensional (2D) lattice Boltzmann method (LBM) is applied to reveal the water dynamic characteristics in GDL, and the computational domain is reconstructed based on the experiment. In-situ experiments, including I–V performance and electrochemical impedance spectroscopy (EIS) tests under flooding conditions, are carried out and analyzed. It is found that the porosity distribution inside the GDL is a crucial factor in water dynamic behavior research. The horizontal liquid water saturation (HSw) under the channel of real GDL (with porosity distribution) at 0.4 relative thickness are 3.2 times, 2.1 times and 3.4 times higher than the ideal GDL (without porosity distribution) in the case of 0.8 mm, 1.2 mm and 2.0 mm, respectively. The numerical simulation and experimental study show that water dynamic characteristics under the rib influence cell performance directly. In our LBM model, the GDL water distribution inconsistency (Varw) under 2.0 mm width rib is 43.1% and 28.0% higher than that under the 0.8 mm and 1.2 mm rib, respectively. With the rib wider from 0.8 mm to 2.0 mm, some parts of cell impedance such as Rmt, Rct, and Lmt increase 64.22%, 98.89%, and 47.46%, respectively. However, GDL under the channel shows no influence on water transport process.