Water Flow Research Articles

3D printing of a multi-performative building envelope: Assessment of air permeability, water tightness, wind loads, and impact resistance

This study investigated the 3D printing feasibility of mono-material facade panels with recycled thermoplastic. The design had integrated performance parameters, namely air permeability, water tightness, resistance to wind loads, and impact resistance, and fabrication parameters in a computational iterative process to inform the geometry topology. The fabrication parameters were integrated and evaluated for geometry accuracy, print path accuracy of 5 mm length, overhang higher than 45°, inner layer adhesion, and adhesion to the print bed. Two panels, measuring 1.6-meter length and 2-meter height, and six connections were fabricated and evaluated in a standardized facade testing rig. The air permeability displayed a larger than 1.5 m3/m2·h permissible Class 1 value due to air gaps in the manufactured panels. The same gaps that occurred during the fabrication process permitted water flow in both panels after 7 minutes of testing. The panels passed standardized serviceability and safety standards for wind load resistance and achieved a maximum E5 class for impact resistance. The structural strength values were 1500 Pa for serviceability, 2250 Pa for safety load, and 3262 Pa for breaking load. These findings demonstrated that 3D-printed geometries have a high potential to facilitate sustainable design strategies by integrating multiple performances within a mono-material building envelope.

Liquid and gas permeabilities of nanostructured layers: Three-dimensional lattice Boltzmann simulation

Liquid water and gas permeabilities in nanostructured catalyst layers (CLs) (pore size ∼10–150 nm) and microporous layers (MPLs) (pore size ∼50 nm-5 μm) are crucial to reduce the mass transport loss in proton exchange membrane fuel cells (PEMFCs). Experimental measurement of their permeabilities poses great challenges due to their brittle and thin characteristics. Presently, considerable discrepancy exists in the reported permeability values for CLs and MPLs in the literature with variation spanning several orders of magnitude. This study digitally reconstructed various nanostructures of similar pore size as CLs and MPLs to calculate their permeabilities using the Lattice Boltzmann Method (LBM) based on no-slip (e.g. for liquid water flow in MPL and CL's secondary pores) or slip condition (e.g. for gas flow in MPL). Analysis was performed to evaluate the range of pore size in nanostructures for the two boundary conditions. A comprehensive investigation was conducted under various parameters such as the Reynolds number (Re), sphere diameter, porosity, and pore structure. The results revealed that permeability exhibits an increasing trend with the diameter and porosity. The predicted permeability of randomly arranged spheres agrees well with established correlations. The random sphere structure demonstrates higher permeability than their body-centered cubic (BCC) and face-centered cubic (FCC) counterparts. Under slip boundary condition, the permeability was enhanced, compared to the no-slip condition. This study's novelty lies in using distinct boundary conditions to assess the permeabilities of liquid and air, based on flow pattern analysis in the CL and MPL pore structures. A new empirical correlation describing the influence of the Knudsen number (Kn) on the slip permeability was developed, exhibiting consistency with simulation across the entire porosity spectrum.

Effect of hypergravity on CHF for water flow boiling in a rectangular channel

Abstract Hypergravity during the maneuver of aircraft can obviously increase the intensity of disturbance in flow boiling. The critical heat flux (CHF) is a critical parameter to prevent the aircraft thermal management system from drying out. On a rotating platform with distilled water as the working fluid, an experimental investigation into the water flow boiling CHF characteristics in a rectangular channel under hypergravity was carried out. In this study, the influence of hypergravity, entry temperature, mass velocity with heating direction on flow boiling CHF have been investigated and discussed. The results show that hypergravity has a clear effect on the CHF by improving two-phase mixing and bubble separation. CHF increases as the hypergravity and mass velocity increase but decreases as the inlet temperature rises. The orientation of the heating has a clear impact on CHF. A new fitting correlation was discovered as a result of the current study.

KATANA - water activation facility at JSI TRIGA, Part II: First experiments

Water as a primary coolant will play an important role in the performance of fusion reactors, as after being irradiated and activated, it causes an ionising radiation field throughout the facility. In direct support of ITER, the KATANA irradiation facility, which utilises a closed-water activation loop and serves as a well-defined and stable high-energy γ and neutron source, was commissioned in 2024 at the TRIGA Mark II research reactor at the Jožef Stefan Institute in Slovenia.A series of first experiments using the KATANA irradiation facility were performed to determine the operational characteristics of the KATANA, i.e. characterisation of the neutron flux within the irradiation component, dose rate measurements, spectrum characterisation of the activated water, and response to a change in reactor power & flow rate. The KATANA facility demonstrated the desired operational characteristics in terms of high and stable water flow rates and high activity values of the observed isotopes 16N, 17N and 19O, which is essential for minimising the experimental uncertainties.The first experiments performed at KATANA provided in-depth knowledge into the operation and capabilities of the facility and essential data to serve as a basis for further, more detailed/benchmark experiments.

Local two-group bubble size model for adiabatic air–water flow in a large diameter pipe using CFD code

Accurate prediction of bubble behavior in large diameter pipes is crucial for evaluating the performance of safety systems, steam generators, and heat exchangers in nuclear systems. Bubble behavior in large diameter pipes under two-phase flow significantly differs from that in small pipes. With the increasing use of computational fluid dynamics (CFD) codes, predicting interfacial area concentration (IAC) is critical for understanding multi-dimensional bubble behavior. This study developed a two-group local bubble size model for bubbly, slug, and churn flows under adiabatic conditions. The model includes correlations for void fraction and bubble sizes of two groups, which were implemented into CFD codes and validated against experimental data from large diameter pipes with low-pressure air–water flow. Results show the model's prediction accuracy surpasses existing correlations. The developed correlations are applicable across a range of flow conditions covering pipe diameters in the range 0.05–0.152 m, pressures from atmospheric to 300 kPa, superficial liquid velocities from 0.25 m/s to 2.85 m/s, and superficial gas velocities from 0.04 m/s to 5.48 m/s. The model is expected to enhance the prediction capabilities of CFD codes for the adiabatic two-group two-phase flows in the large diameter pipes.

Ensemble Machine Learning-Based Virtual Multiphase Flow Metering in High Gas/Oil Ratio and Water-Cut Reservoirs

By combining data-driven ensemble machine-learning algorithms and historical oil field portable test reports, this paper proposes a Data-Drive Multiphase Virtual Flow Meter (DD-MVFM) that estimates oil, gas, and water flow rates, provides real-time monitoring, and predicts future production for a 6-month period with appropriate accuracy. The proposed DD-MVFM utilizes the existing hardware used for measurements of basic variables such as temperature, and pressure at different locations at the well-head structure. The DD-MVFM can be employed in three ways. The first way is to be used as a verification tool for multiphase physical flow meters (MPFMs), making sure they are working properly and increasing confidence in the collected readings. The second way is to use the DD-MVFM as a redundant tool when the MPFMs are not available or going through maintenance. The third way, which is the main objective of our research, is to employ the proposed DD-MVFM as a stand-alone for the complete replacement of current and future MPFM installments. This, significantly lowers the operating cost, reducing the required portable field tests, and saving the need to build a major infrastructure for the set-up of MPFMs for new oil wells. Consequently, this contributes to the ambitious goal of reducing CO2 emissions. The DD-MVFM's development involves the fusion of data wrangling and machine learning algorithms for optimal performance. Initial testing indicates an 85% correlation with the actual production rates, with potential for further improvement as more field test data is incorporated, making it a pioneering solution in the field of oil and gas management.

Identifying Subsurface Connectivity From Observations: Experimentation With Equifinality Defines Both Challenges and Pathways to Progress

ABSTRACTLinkages between landscapes and streams are increasingly described in terms of hydrological connectivity. The ability to effectively distinguish different patterns of water movement through catchments makes connectivity particularly interesting to both scientists and practical water managers. Hydrometric data (groundwater levels, soil moisture and streamflow) are often employed to infer the connection between the landscape and its drainage network. Such observational data, however, are insufficient to infer subsurface connectivity in humid settings with perennial stream flow, due to the risk of equifinality. To quantify how much subsurface flow patterns can differ and still be consistent (equifinal) with comprehensive observations of hillslope groundwater levels and stream runoff (the hydrometric data), this study used a modelling experiment based on a well‐characterised field site. Particle‐tracking simulations at different flow rates defined the water flow paths and transit times of two virtual hillslopes that differed profoundly in the vertical distribution of the saturated hydraulic conductivity. Even though the simulated weekly stream flows and groundwater levels were similar (i.e., the hillslopes were hydrometrically equifinal) particle velocities and water ages at specific locations along these hillslopes differed by orders of magnitude. Flow path lengths and catchment transit times varied up to several 100%. The hillslope‐ and stream‐based metrics used to describe connectivity also varied with stream flow rates. These results underline the need to recognise the risks for equifinality when inferring subsurface connectivity from hydrometric observations alone, even when those observations are comprehensive. The results also highlight the value of model simulations for quantifying the uncertainty in the inferred connectivity, targeting the best sampling locations/times to reduce this uncertainty with tracer data and better understanding the way connectivity influences stream chemistry.

Mesoscale modeling on the influence of surfactants on seepage law during water injection in coal

To investigate the mesoscopic influence of surfactants on seepage law during water injection in coal seam, this paper innovatively establishes a fluid transport lattice Boltzmann (LBM) model by incorporating the seepage resistance generated from the porous media and external forces, which embodies the impact of wettability degree resulted from cocamidopropyl betaine (CAB), sodium dodecyl sulfate (SDS), and coconutt diethanol amide (CDEA) reagents at a 0.1% concentration. The main conclusions derived from this investigation are as follows: Firstly, as the lattice number in the X direction increases, the average seepage velocities in coal samples treated by deionized water, 0.1% CAB, 0.1% SDS, and 0.1% CDEA reagents (Nos. 1, 2, 3, and 4) exhibit three distinct stages: rapid decline, slow decline, and steady decline; in comparison to raw coal sample, modified coal samples demonstrate decreases of 20.84%, 33.91%, and 61.70%, respectively. Secondly, the critical values of displacement pressure difference exist during the phenomenon that modified reagents spread out in the entire flow channel, which are 3.5 MPa, 3.5 MPa, and 5.2 MPa, respectively, for coal samples Nos. 2, 3, and 4; this signifies that surpassing these critical values help prevent issues such as blank belts within the wetting range and insufficient dust control. Finally, at a displacement pressure difference of 0.01 (lattice unit), the average velocity ratios for samples (Nos. 2, 3, and 4) are 0.78, 0.56, and 0.37(lattice unit), respectively; notably, the water flow velocities in modified coal samples are lower compared to that in raw coal sample, indicating that the addition of surfactants impede the seepage process of water injection in coal seam. Moreover, when the displacement pressure difference reaches 0.03 (lattice unit), the velocity ratio of CDEA-modified coal sample exceeds 100%; this means that when the displacement pressure difference surpasses 15.6 MPa, the water injection effect of CDEA-modified coal sample begins to be improved. These research findings offer a theoretical basis for enhancing water injection technology in coal mines.

Worldwide consequences of a mid-Holocene cold event in the Nordic Seas

The present interglacial is a relatively warm and stable period, especially compared to the preceding glacial time. However, the Holocene has seen the emergence of several remarkable cold events, some with worldwide consequences. Leveraging marine records from the Nordic Seas, we provide the first detailed account of a cold event centered around 6.8 ka BP. Utilizing paleoceanographic proxies and advanced modeling, we unveil a distinct subsurface water cooling, associated with a stepwise increase in sea-ice cover in the eastern Fram Strait. Our findings emphasize the role of Greenland Sea deep convection onset and the subsequent westward shift in Atlantic Water flow, enabling sea-ice advection from the Barents Sea. The heightened sea-ice cover weakened Atlantic Water advection, perturbing thermohaline circulation in the eastern Nordic Seas. These perturbations propagated worldwide, affecting North Atlantic deep-water circulation, inducing widespread hemispheric cooling, shifting the Intertropical Convergence Zone southward, and weakening the East Asian monsoon. Incorporating results from the Transient simulations of Climate Evolution of the last 21,000 years (TraCE-21ka) supports and augments proxy-based paleoreconstructions, underscoring sea-ice dynamics and ocean circulation's critical influence. This study highlights the potential for localized cold events within ostensibly warm climatic intervals. It underscores the need to comprehend their mechanisms for precise climate predictions and informed policymaking toward a sustainable future.

Rainfall-induced microplastic fate and transport in unsaturated dutch soils

Microplastic pollution has become a growing concern in terrestrial ecosystems, with significant implications for environmental and human health. Understanding the fate and transport of microplastics in soil environment is crucial for effective mitigation strategies. This study investigates the dynamics of microplastic (Low-density polyethylene (LDPE), polybutylene adipate terephthalate (PBAT), and starch-based biodegradable plastic) transport in unsaturated soils under varying rainfall intensities and soil types, aiming to elucidate the factors influencing their behavior. Effluent samples were analyzed to measure microplastic transport, with microplastic balance analysis ensuring experimental accuracy. The setup replicated real-world flow conditions, providing insights into microplastic transport in unsaturated porous media. Microplastic balance analysis revealed high recovery factors (between 64 % and 104 %), indicating the reliability of the experimental approach. Microplastic transport varied significantly between sandy loam and loamy sand soils, with loamy sand soils exhibiting higher wash-off rates due to their unique properties. LDPE microplastics showed a higher tendency to detach from soil columns compared to PBAT and starch-based particles. Higher rainfall intensity in loamy sand soil columns resulted in an increased washout of LDPE, PBAT, and starch-based particles by 92 %, 144 %, and 85 %, respectively, compared to low rainfall intensity. In sandy loam soil, increased rainfall intensity resulted in a significantly higher washout of LDPE, PBAT, and starch-based particles with percentages of 93 %, 69 %, and 45 %, respectively. This underscores the important role of water flow in mobilizing microplastics within the soil matrix.

Dynamic visualization study of in situ cleaning of polystyrene microparticles off silicon wafer surface

With the improvement of chip performance, the requirements for cleaning the surface of silicon wafers are becoming higher. However, due to equipment and technology, it is difficult to observe the complex motion processes of particles at the microscopic scale. In this paper, an in situ dynamic visualization experiment on the cleaning of Polystyrene Latex (PSL) on the surface of silicon wafers is carried out by using a high-speed camera and image processing software. The mechanical behavior of PSL particles in fluid was investigated on a microscopic scale, and the trajectory and force of the polystyrene particles on the surface of the wafers were visualized, which provided a new perspective for understanding the complex cleaning process. Theoretical models were developed to explain the motion characteristics of the particles by calculating parameters such as van der Waals force, surface tension, and trailing force, and these models provide a theoretical basis for optimizing the cleaning process. There are four particle motion modes in the fluid: (1) interface capture, where the particles on the surface of silicon wafer are trapped by gas–liquid interface under surface tension; (2) particle collision, where the particles captured by the water film collide with the particles on the wafer surface to make the latter leave the silicon wafer; (3) jump attachment, where the particles jump and attach to the surface of the particle group under the action of lift; and (4) wall surface movement, where the particles start up under the action of water flow and then leave the silicon wafer quickly.

A comprehensive review of effective parameters to improve the performance of the Savonius turbine using a computational model and comparison with practical results

Amidst growing global concerns over climate change and escalating greenhouse gas emissions from fossil fuels, the pursuit of renewable energy sources has become critical. This study focuses on harnessing hydropower using Savonius turbines, which are known for their efficiency in generating energy at lower flow rates. However, the intrinsic low efficiency of these turbines necessitates precise optimization tailored to specific river or channel conditions. In this research, we optimized the performance of Savonius turbines by analyzing key parameters such as the height-to-diameter ratio, blade twist, and the integration of multi-stage configurations with deflectors. Our findings reveal significant efficiency improvements through strategic modifications. Specifically, by reducing the height-to-diameter ratio from 1.2 to 0.8 and maintaining a Tip Speed Ratio (TSR) of 0.6, the power coefficient increased by 15%, from 0.33 to 0.38. Further optimization was achieved by adjusting the blade twist angle, with an increase in power coefficient up to an optimal angle of 45°, beyond which efficiency declined. Implementing a two-stage turbine setup with a 90-degree phase difference between stages further improved the power coefficient to 0.51 at the same TSR. Additionally, the use of deflectors, particularly at a 90° angle, significantly boosted the power coefficient, highlighting their effectiveness in optimizing water flow impact on the turbine. This comprehensive study not only advances the understanding of Savonius turbine optimization but also contributes to broader renewable energy applications. The research offers critical insights into sustainable hydroelectric power generation, providing practical solutions to enhance turbine performance for real-world applications.

Development of membrane distillation powered by engine exhaust for water desalination

To address water shortage in arid areas and make use of waste heat, an experimental investigation is presented for a novel system of air gap membrane distillation unit driven by an engine exhaust heat source for the development of an on-board car water desalination. The design of the gas-to-water heat exchanger is presented and optimized. The system’s performance, governed by the achieved feed water temperature and measured by the output vapor mass flux, is evaluated with time under varying operational parameters, including engine load, engine speed, and feed water flow rate, with the analysis of production cost for economic viability. Experimental results revealed that higher engine loads and speeds lead to rapid temperature increase of the feed water, enhancing the efficiency of the membrane distillation process and increasing the permeate flux. Notably, a maximum permeate flux of 45 kg/m2h was achieved after 40 min of operation. A minimum production cost of 3.2 $/m3 is estimated at an engine load of 35 N.m. With production costs ranging from 3.2 to 5.8 $/m3, the proposed system emerges as a highly competitive option when compared with other membrane distillation systems driven by waste heat in literature. This study underscores the potential of utilizing waste heat from car engines for cost-effective and sustainable water desalination, paving the way for further development and implementation of the system as a mobile desalination unit for different applications.

Study on the influence characteristics of multi-working condition parameters on membrane electrode type CO2 electrolyzer

The electrochemical conversion of carbon dioxide (CO2) into basic chemicals or carbon-based fuels is a promising new strategy for carbon resource utilization. Within this domain, solid-electrolyte CO2 electrolyzer demonstrate significant potential for the continuous production of pure formic acid solutions. This study, leveraging a 4 cm2 visualization electrolyzer, explores the impact of three working condition parameters on performance: working voltage, gas flow rate, and the intermediate chamber water flow rate. It compares the variations in current density, formic acid concentration, and the distribution of liquid water on the cathode side under different working conditions. The results indicate that the working voltage, current density, and formic acid yield are all positively correlated; overly low gas flow rates can lead to CO2 deficiency and diminished electrolyzer performance; concentration control of the formic acid solution is effectively achieved by adjusting the intermediate chamber water flow rate; and during the electrolyzer reaction process, almost all of the liquid water is positioned at the bends downstream of the cathode flow channel.

Numerical Simulation of Two-Layer Shallow Water Flows. Exchange Flow in the Lombok Strait

Numerical Simulation of Two-Layer Shallow Water Flows. Exchange Flow in the Lombok Strait

Double parametric based solution of fuzzy unconfined aquifer problem using Laplace transforms method

The Boussinesq equation describes the model for horizontal water flow in unconfined aquifers without precipitation, a topic that has been extensively studied in the literature. However, the parameters, as well as the initial and boundary conditions, are often assumed to be exact. In reality, these conditions may be incomplete or uncertain due to limited knowledge, insufficient information, or errors introduced by humans or machines. The fuzzy set theory has recently been successfully employed to model such uncertainties. This article investigates the analytical solution of the one-dimensional Boussinesq equation in a fuzzy environment. The objective of this research is to investigate the recharge and discharge of a semi-infinite unconfined aquifer adjacent to a lake. For the present investigation, uncertainties in terms of fuzzy are considered only for the involved initial and boundary conditions of the problem, whereas other parameters are considered as crisp or exact. The analysis employed the double parametric form of a fuzzy number alongside Laplace transform techniques. The obtained solutions were then compared with existing results in specific cases to validate their accuracy.

Analysis of forces on nodules during Coandă-effect-based hydraulic collection

The nodule pickup device is a crucial component of a deep-sea mining system. It is widely perceived that leveraging water flow for the separation and retrieval of nodules is a promising approach. A series of experiments and numerical simulations were conducted to examine the impact of non-dimensional parameters on the force characteristics and flow field of the particle in Coandă-effect-based hydraulic collection. The results showed that the lift coefficient of the particle initially increased before subsequently diminishing from the jet nozzle to the rear. Notably, the lift coefficient α reached its maximum at the convex curved surface between x/d = −0.17 and 0.33. Furthermore, a distinct linear correlation was established between the maximum lift coefficient αmax and Froude number Fr across varying h/d, and an empirical formula for predicting the lift coefficient was developed through data fitting. Upon experimental validation, the prediction exhibited a maximum error of less than 20%. Additionally, numerical simulations revealed that the particle significantly influenced the flow dynamics within the collection area, and the flow field characteristics and the particle forces can be corroborated with each other. The findings not only provided a reliable quantitative tool for assessing the particle force but also facilitated precise predictions of collection performance, aiding in the selection of optimal operational parameters in deep-sea hydraulic collection.

Optimizing Nitrate Fertilizer Production Using Plasma-Activated Water (PAW) Technology: An Analysis of Dielectric Properties

This study investigates the potential of Plasma-Activated Water (PAW) technology for the production of nitrate fertilizer, focusing on the dielectric properties of plasma-treated water, such as the dielectric constant and dielectric loss factor. The research aims to elucidate the impact of plasma treatment and varying water flow rates on these properties. An experimental approach was employed wherein ion-free water was subjected to plasma treatment at different flow rates (0.5, 1.0, and 2.0 L/min) and durations (1, 2, and 3 h). The results reveal a marked enhancement in the dielectric properties of the water following plasma treatment, with the most significant improvements observed at a flow rate of 0.5 L per minute and a treatment duration of 3 h, and dielectric efficiencies of 97.82%, 97.21%, and 96.61% achieved at flow rates of 0.5, 1.0, and 2.0 L/min, respectively. These findings demonstrate that PAW technology enhances the efficiency of nitrate fertilizer production by optimizing energy storage and reducing energy losses. The study underscores the potential of PAW as a sustainable, environmentally benign alternative to conventional chemical fertilizers, contributing to more efficient and sustainable agricultural practices.

Assessing the Soil Infiltration Rate of Alpine Meadows Using the Electrolyte Tracer Method

ABSTRACTGrassland on the Qinghai‐Tibet Plateau is highly susceptible to climate change and human activities, and vegetation degradation can affect biodiversity and soil erosion. Soil infiltration is a crucial water flow process that determines the amount of runoff and water storage capacity, and it is of great importance in maintaining biodiversity. This research investigated the effects of vegetation degradation and soil rates on soil infiltration rate and processes using the electrolyte tracer method. This technique accurately calculated soil infiltration rate by tracking continuous changes in the solute concentration change process throughout the experimental period and did not require calibration. Findings indicate that vegetation type, root mass, soil water content and soil porosity significantly affect soil infiltration rate. In particular, root mass was found to have a negative effect on soil infiltration rate. Soil moisture content initially dominated soil infiltration, but subsequently, soil porosity became increasingly influential in affecting infiltration in degraded meadow. Soil infiltration capacity varied more with vegetation type than with surface runoff. Shrub meadows had the highest infiltration rate followed by normal alpine meadows and degraded meadows, indicating the importance of vegetation on soil infiltration. The research also shows that mixed shrub and meadow can improve the ecological environment by introducing a more complex root system and increasing the infiltration rate. The electrolyte tracer method was used as an alternative to other methods that can be used in different environments than the one studied in this research.

Material balance analysis of water influx into an undersaturated oil reservoir using pot aquifer model: a case study

ABSTRACT Early water breakthrough due to pressure depletion is often attributed to a strong water drive and must be established to avoid wrong reserves estimation and planning. In this study, we evaluated the Safsaf C reservoir, an undersaturated oil reservoir in North Africa that experienced early water breakthrough at 62 days after the commencement of oil production. To establish or disprove the presumption of it producing under a strong water drive, we critically analyzed the reservoir using the Material Balance Equation (MBE) coupled with the pot aquifer water influx model. The Campbell plot showed a weak aquifer, and the Solution plot confirmed aquifer presence. The pot aquifer plot gave the original aquifer in place an estimate of about 28.42 mmRB, which is about half the size of the estimated hydrocarbon pore volume of 51.15 mmRB. Water influx plots produced improved Oil initially in place (OIIP) estimates in the range of 11.50 to 12.20 mmSTB. The aquifer influx profiles show that water encroaches into the reservoir at a rate of 742 rbl/d. This approach is suitable when little is known about the aquifer and provides reliable estimates of OIIP and the degree of aquifer support for reservoirs bounded by small aquifers.