Surface Tension Of Fluid Research Articles

Pressure-Surface Tension-Temperature Equation of State for n-Alkanes.

Herein, the geometric similitude concept is applied to propose a cubic equation that relates surface tension, saturation pressure, and temperature for n-alkanes. The input properties for each fluid are the molecular mass, pressure, temperature, and compressibility factor at the critical point. The model is applied to temperatures below 0.93·Tc (critical point temperature). A total of 2429 surface tension values have been selected for 32 n-alkanes. The parameters of the model have been obtained with a fit of the surface tension values for 19 pure n-alkanes that are randomly chosen. Then, it is tested for the other 13 pure n-alkanes and used to predict the surface tension for 11 binary and 4 ternary mixtures. These predictions are compared with the reported experimental data. For pure n-alkanes, the overall absolute average deviation is 2.4%, including the correlation and testing sets. No additional adjustable coefficients are used for mixtures, yielding an overall absolute average deviation of 2.98% for the binary systems and 7.97% for the ternary ones. The results show that the model is accurate enough for predictions and that the highest deviations are due to the lack of agreement in the values of surface tension of pure fluids obtained from different sources.

Effect of surface tension of interstitial fluid on the physicochemical properties of layered double magnesium and aluminum hydroxides obtained by solid-phase synthesis

The paper presents the results of studies of the effect of the surface tension of the interstitial fluid on the structural and surface properties (specific surface area and pore volume, pore diameter distribution) of layered magnesium and aluminum double hydroxides (Mg-Al LDH) obtained by the interaction of AlCl3·6H2O, MgCl2·6H2O and ammonium carbonate. The equations connecting the specific surface area and the specific pore volume of the synthesized Mg-Al LDH samples with the surface tension of the interstitial medium are obtained. It is shown that the substitution of the aqueous medium in the pore space for acetone before drying the synthesized Mg-Al LDH allows to significantly increase the capacity of the adsorption monolayer of products and does not significantly affect the mechanism of the sorption process.

A combined density gradient theory with equation of state model for the study of surface tension of refrigerant fluids

A combined density gradient theory (DGT) with an equation of state (EoS) model has been employed for describing the surface tension of 26 pure refrigerant fluids. Two EoSs were considered to be employed in the model development. The first one is the Carnahan–Starling hard-sphere equation with the perturbation term of Dohm-Prausnitz (CS-DP EoS) and the second one is the modified version of that EoS, i.e., MCS-DP. Then two different DGT-based models (DGT + CS-DP and DGT + MCS-DP) were employed for calculating the surface tension of pure refrigerants. The surface tension data source was provided from NIST databank and several original papers, as well. Both DGT models used one unique value for the influence parameter for each fluid. The DGT + MCS-DP model with the average absolute deviations (AADs) of 4.23% was found to be almost as accurate as DGT + CS-DP model with AAD of 4.84% for the correlation of NIST data. But in case the calculation of experimental surface tensions, DGT + CS-DP and DGT + MCS-DP models led to AADs of 5.88% and 3.74%, respectively, which reveals very well the superiority of DGT + MCS-DP against DGT + CS-DP one. All calculations on the surface tension of studied refrigerants were carried out in 0.45–0.95 of reduced temperature. Then, the degree of accuracy of DGT + MCS-DP model has also been compared with some simple empirical equation based on the corresponding states principle.

Simulations of liquid metal flows over plasma-facing component edges and application to beryllium melt events in JET

Navier–Stokes simulations of liquid beryllium (Be) flows over the straight edge of plasma-facing components are carried out in conditions emulating upper dump plate (UDP) melting observed experimentally in JET. The results demonstrate the existence of three main hydrodynamic regimes featuring various degrees of downstream flow attachment to the underlying solid surface. Transitions between these regimes are characterized by critical values of the Weber number, which quantifies the relative strength of fluid inertia and surface tension, thereby providing a general stability criterion that can be applied to any instance of transient melt events in fusion devices. The predictive capabilities of the model are tested by comparing numerical output with JET data regarding the morphology of the frozen melt layers and the location of Be droplets splashed onto nearby vacuum vessel surfaces as a result of disruption current quench plasmas interacting with the solid Be tiles protecting the upper main chamber regions. Simulations accounting for the coupling between fluid flow and heat transfer confirm the key role played by re-solidification as a stabilizing process, as previously found through macroscopic melt dynamics calculations performed with the MEMOS-U code. The favourable agreement found between the simulations and the general characteristics of the JET Be UDP melt splashing give confidence that the same approach can be applied to estimate the possibility of such mechanisms occurring during disruptions on ITER.

Capillary Interactions, Aggregate Formation, and the Rheology of Particle-Laden Flows: A Lattice Boltzmann Study

The agglomeration of particles caused by the formation of capillary bridges has a decisive impact on the transport properties of a variety of at a first sight very different systems such as capillary suspensions, fluidized beds in chemical reactors, or even sand castles. Here, we study the connection between the microstructure of the agglomerates and the rheology of fluidized suspensions using a coupled lattice Boltzmann and discrete element method approach. We address the influence of the shear rate, the secondary fluid surface tension, and the suspending liquid viscosity. The presence of capillary interactions promotes the formation of either filaments or globular clusters, leading to an increased suspension viscosity. Unexpectedly, filaments have the opposite effect on the viscosity as compared to globular clusters, decreasing the suspension viscosity at larger capillary interaction strengths. In addition, we show that the suspending fluid viscosity also has a non-trivial influence on the effective viscosity of the suspension, a fact usually not taken into account by empirical models.

Thermocapillary Fingering of a Gravity-Driven Self-Rewetting Fluid Film Flowing Down a Vertical Slippery Wall

Abstract The surface tension of a self-rewetting fluid (SRF) has a nonmonotonic variation with the increase of temperature, implying potential applications in many industrial fields. In this paper, flow patterns and stability analysis are numerically performed for a gravity-driven self-rewetting fluid film flowing down a heated vertical plane with wall slip. Using the thin film theory, the evolution equation for the interfacial thickness is derived. The discussion is given considering two cases in the review of the temperature difference between the interfacial temperature and the temperature corresponding to the minimum surface tension. The base state of the two-dimensional flow is first obtained, and the influence of the Marangoni effect and slippery effect is analyzed. Then linear stability analysis and related numerical verification are displayed, showing good consistency with each other. For a low interfacial temperature, the Marangoni promotes the fingering instability, and for a high interfacial temperature, the inverse Marangoni impedes the surface instability. The wall slip is found to influence the free surface in a complex way because it can either destabilize or stabilize the flow of the free surface.

Measuring the viscosity of air with soapy water, a smartphone, a funnel, and a hose: An experiment for undergraduate physics students

We investigate the spontaneous motion of a soap film in a conical geometry connected to a long tube and show how it can be used to measure the dynamic viscosity of air. In contrast to other techniques that are complicated to implement and require expensive and sophisticated equipment, this measurement method relies only on soapy water and three everyday life objects: a smartphone, a funnel, and a hose. More precisely, to determine the viscosity of air, we use a smartphone to record the spontaneous motion of a soap film placed in a funnel when the motion of the film is quasistatic and the flow of air escaping the geometry is viscously dominated. This simple experiment should be of value to undergraduate physics students in learning about effects of both fluid viscosity and surface tension (another fluid property which they could also measure with a smartphone; Goy et al., Phys. Teach. 55, 498–499 (2017)), and the usefulness of reasonable approximations in physics.

Effect of a novel shrinkage-reducing polycarboxylate superplasticiser on plastic shrinkage cracking of mortars

Plastic shrinkage cracking propagating at early ages inevitably impairs the performance of concrete structures. To mitigate this, using a recently developed shrinkage-reducing polycarboxylate superplasticiser (SR-PCA) with outstanding shrinkage-reducing and water-reducing effectiveness can be a promising approach. The present work aims to investigate the effect of SR-PCA on plastic shrinkage cracking and to clarify the underlying mechanisms. For comparison, a traditional polyether type shrinkage reducing admixture (SRA) and a polycarboxylate superplasticiser (PCA) were also used. Based on the investigations on horizontal shrinkage, settlement, bleeding, evaporation mass loss, cement hydration, surface tension of pore fluid and capillary pressure, the underlying working mechanisms of SR-PCA were identified. The results indicate that SR-PCA is able to reduce the crack area, maximum crack width and average crack width by up to 55, 48 and 50%, respectively. Furthermore, prolonging the bleeding duration and initial time of capillary pressure build-up caused by retarding the cement hydration, lowering the evaporation mass loss, and a lower development rate of capillary stresses and capillary pressure peak value induced by decreasing the surface tension of pore fluid are responsible for preventing the plastic shrinkage cracking of mortars containing SR-PCA.

The wettability of electron spun membranes by synovial fluid.

Aseptic loosening due to periprosthetic osteolysis has been accepted as one of the leading causes of revision procedures in patients with previous joint arthroplasty. Recently, several strategies for suppression of osteolysis were proposed, mostly based on biological treatment such as mitigation of chronic inflammatory reactions. However, these biological treatments do not stop the debris migration but only reduce the inflammatory reaction. To address this shortcoming, we propose the concept of ultrahigh molecular weighted polyethylene particles filtration storage by electrospun membranes. Firstly, the surface tension of synovial fluid (SF) is obtained by use of a pendant droplet. Secondly, the contact angle of the electrospun membranes wetted by two different liquids is measured to obtain the free surface energy using of the Owens–Wendt model. Additionally, the wettability of electrospun membranes by SF as a function of technology parameters is studied.

Investigation of the surface tension of water-based Fe3O4 magnetic fluids under magnetic field: The effect of surfactants

In this work, water-based Fe3O4 magnetic fluids were prepared and the effect of surfactants on magnetic surface tension was investigated under a constant magnetic field. Different surfactants include anionic surfactants citric acid and sodium dodecyl sulfate (SDS); nonionic surfactants polyvinyl pyrrolidone (PVP K30) and polyethylene glycol(PEG-600) were employed to modify Fe3O4 nanoparticles. After the modification, the stability of Fe3O4-SDS magnetic fluid improved greatly, with the zeta potential improved to −40.5 mV compared to Fe3O4 magnetic fluid (−22 mV) without surfactants. X-ray diffraction and Fourier transform infrared spectroscopy were employed to characterize the crystalline and the surface changes. The results showed that the surfactant was successfully coated on the surface of Fe3O4 without changing the crystallinity. The surface coverage of nanoparticles by the surfactants caused a smaller saturation magnetization than uncoated Fe3O4 nanoparticles while keeping the superparamagnetic behavior. More importantly, the surface tension of the magnetic fluid was measured by the Du Noüy ring method, and an in-depth study of the magnetization time and direction on the magnetic surface tension has been carried out. Visual characterization of the cluster structure was carried out for an in-depth analysis of the influence of the external magnetic field on magnetic surface tension.

Содержание кремния в крови и синовиальной жидкости больных ревматоидным артритом: клинико-патогенетическая значимость микроэлементоза

Актуальность. Распространенность ревматоидного артрита (РА) среди населения земного шара составляет около 1 %, а среди отдельных популяций людей достигает 5–7 %. К факторам риска развития и высоких темпов прогрессирования РА относятся большие концентрации во вдыхаемом воздухе кварца (диоксида кремния), токсическое воздействие которого рассматривается как один из мощных патогенетических факторов этого заболевания. Цель. Оценка клинико-патогенетической значимости кремниевого микроэлементоза при РА. Материалы и методы. Обследованы 83 больных РА (22 % мужчин и 78 % женщин в возрасте от 22 до 75 лет; в среднем 45 лет). Длительность заболевания от первых признаков его манифестации составила 9 лет. Системная форма болезни диагностирована в 19 % случаев, серопозитивный РА по ревматоидному фактору установлен в 68 % наблюдений, по антицитруллиновым антителам — в 80 %. Содержание кремния (Si) в сыворотке крови и синовиальной жидкости у 19 больных определяли с помощью атомно-абсорбционного спектрометра SolAAr-Mk2-MOZe с электрографитовым атомизатором (Великобритания). С использованием компьютерного тензиометра PAT2-Sinterface (Германия) исследовали параметры поверхностного натяжения сыворотки крови и синовиальной жидкости при времени «жизни поверхности» 0,01 с, стремящемся к бесконечности, подсчитывали их соотношение. Результаты. РА сопровождается отсутствием достоверных изменений уровня кремниемии. Микроэлементоз Si связан с клиническими, рентгенологическими и сонографическими признаками течения заболевания, степенью активности и тяжестью артрита, а кремниевый дисбаланс участвует в патогенетических построениях суставного синдрома, поражении скелетных мышц, периферической нервной системы, причем показатели Si в крови могут обладать прогностической значимостью.

Surface tension and density of dielectric heat transfer fluids of HFE type-experimental data at 0.1 MPa and modeling with PC-SAFT equation of state and density gradient theory

Hydrofluoroethers (HFEs) belong to a family of promising fluids that find application potential both in scientific research and in many industrial areas. These include electronics cooling, cascade refrigeration, heat transfer fluids, lubricant carriers or even rinsing agents. However, the thermophysical properties of HFEs required for an effective design of technical applications are only vaguely described and the available experimental data for thermodynamic and transport properties are still limited. In order to improve the description of HFEs, new experimental measurements of liquid density and surface tension at pressure of 0.1 MPa and temperatures from 260 to 338 K were carried out with a series of five HFEs; namely HFE-7000, HFE-7100, HFE-7200, HFE-7300, and HFE-7500. Liquid density was determined from a single sinker buoyancy method with an expanded uncertainty of 0.50 kg•m−3. The Wilhelmy plate method and the du Noüy ring method were used for the measurement of surface tension with expanded uncertainties of 0.068 mN•m−1 and 0.18 mN•m−1, respectively. In the modelling part, a consistent fluid property model was developed based on the physically based equation of state PC-SAFT. Additionally, regarding polarity of HFEs, empirical correlation for dipole moment was addressed. In case of larger HFE molecules, it was determined that the polar modification named PCP-SAFT, provides only marginal correction. The equations were combined with the density gradient theory (DGT) in order to model vapor-liquid phase interface and predict the surface tension. DGT+PC-SAFT was found to provide good predictions for the surface tension of the five selected HFEs.

Anti-icing fluids interaction with surfaces: Ice protection and wettability change

Some aircraft anti-icing fluids can dangerously weaken on hydrophobic surfaces. However, information about such fluids and surfaces was not full. Therefore, we considered the interaction of commercially available Newtonian and pseudo-plastic anti-icing fluids with super-hydrophilic and hydrophobic aluminum surfaces. In freezing rain simulations, no noticeable surface effect was observed on fluid endurance times at 10% ice coverage of the surfaces. The difference with previous works can be caused by fluid surface tensions, the contact angle hysteresis of test plates, and fluid viscosity (the last is irrelevant for Newtonian fluids). In further comparative studies, the roughness must also be considered because on rough hydrophobic surfaces the Newtonian fluid took longer to freeze once ice coverage surpassed 20% compared to smooth super-hydrophilic surfaces. Furthermore, the fluid physical adsorption in the surface texture leads to the drifting of receding contact angles of water on hydrophobic surfaces, thereby worsening their water-repelling. Thus, smooth hydrophobic surfaces are probably the preferred solution for ice mitigation systems contacting aircraft anti-icing fluids.

Application of silica (SiO2) nanofluid and Gemini surfactants to improve the viscous behavior and surface tension of water-based drilling fluids

Further studies into drilling fluids especially to reduce the use of oil and synthetic-based drilling fluids are ever-growing due to their contributions to environmental pollution. This study, therefore, attempts to evaluate the thermal, viscosity, surface tension, and filtration loss properties of water-based drilling fluids (WBDFs) upon the addition of Gemini surfactant-silica nanofluid. This surfactant-nanofluid was formed by dissolving silica nanofluid in the surfactant solution, and ultra-sonication was used to attain homogeneity. Characterization of the Gemini surfactant-silica (SiO2) nanofluid was done by Fourier Transform Infrared Spectroscopy (FTIR). The viscosity, surface tension, and filtration loss properties were studied using the rheometer, tensiometer, and low-pressure, low-temperature (LPLT) filter press respectively. The experimental results showed that Gemini surfactants contributed to the highest increase in drilling fluid viscosity compared to a conventional surfactant. Also, when combined with silica-nanoparticles showed better thermal stability with an 11% average change in viscosity with increasing temperature and a decrease in surface tension and filtration loss both showing a 17% and 12% decrease respectively.

Study on Nano-Materials Improving Fracturing Fluid Performance and Oil Displacement Mechanism

Because of its characteristics and advantages, nano-materials can significantly improve the performance of fracturing fluid after being added to fracturing fluid. The research on the action mechanism of nano-materials in fracturing fluids is the theoretical basis and basis for developing functional fracturing fluids. At the nanoscale (50nm), SiO2 was modified with C8 and quaternary ammonium salt (QAS),synthesizing the Hydrophobic nano-materials SiO2-C8 and hydrophobic charged nanomaterials SiO2-QAS .The dispersion method, addition amount, compatibility stability and rheological properties of SiO2, SiO2-C8 and SiO2-QAS nano-materials in SRFP clean fracturing fluid system were studied. By means of quantitative simulation methods, the adsorption structure model and adsorption kinetics of nano-materials on sandstone surface were established The model analyzes the adsorption and oil-water separation characteristics of nano-materials on the sandstone surface. The research results show that the three nano-materials have better dispersion stability in the clean fracturing fluid, can effectively reduce the surface tension of the fracturing fluid, and show better temperature and shear resistance; Due to the special adsorption characteristics and specific interface effects of SiO2-C8 and SiO2-QAS nano-materials, which are beneficial to the replacement of oil molecules on the sandstone surface after the addition of fracturing fluid, and promote the separation of oil and water. The addition of SiO2-C8 and SiO2-QAS nano-materials can effectively improve the performance of fracturing fluid, improve the oil displacement effect on the surface of sandstone, and achieve the purpose of reducing oil saturation and increasing the fluidity of crude oil within the range of fracturing fluid. The results can be used as a reference for the development of functional fracturing fluid and the progress of fracturing technology for tight oil and shale oil.

Research on the capillary penetration mechanism of cutting fluid supplied by electrostatic spraying in diamond wire sawing

Friction performance of cutting fluid has significant influence on silicon wafer surface quality in diamond wire sawing. In this paper, capillary penetration mechanism of cutting fluid supplied by electrostatic spraying in diamond wire sawing was researched, which has a great influence on the lubrication effect of cutting fluid. The influences of charging voltage of cutting fluid supplied by electrostatic spraying (named ES-cutting fluid) on the charge-to-mass ratio, contact angle and surface tension of ES-cutting fluid were tested. Through theoretical calculation, the effects of charging voltage of ES-cutting fluid on capillary penetration and lubrication of water-based cutting fluid are studied. The relationship between capillary penetration depth and friction performance of ES-cutting fluid was established. The kinetic model of ES-cutting fluid penetrated capillary was studied, four ball friction experiment and diamond wire saw cutting experiment were carried out to verify the rationality of model. The experimental results show that the capillary penetration depth first increases with the increase of charging voltage, reaches the maximum when the charging voltage is −3 kV, and then decreases with the increase of charging voltage. The capillary penetration depth increases from 7.05 μm to 7.55 μm when the charging voltage increases from −0 kV to −3 kV, and then decreases to 6.25 μm when the charging voltage increases from −3 kV to −6 kV. Friction coefficient first decrease with the increase of charging voltage, reaching the minimum at −3 kV, and then increase with the increase of charging voltage. Cutting force first decrease with the increase of charging voltage, reaching the minimum at −4 kV, and then increase with the increase of charging voltage. Friction coefficient and cutting force decrease with the increase of capillary penetration depth, which indicates that the improvement of capillary permeability of cutting fluid is helpful to improve the cutting performance of diamond wire sawing.

A REVIEW OF SMOOTHED PARTICLE HYDRODYNAMICS FAMILY METHODS FOR MULTIPHASE FLOW

With meshfree and fully Lagrangian features of particle methods, smoothed particle hydrodynamics (SPH) is suitable to achieve high-accurate simulations of multiphase flows with large interfacial deformations, discontinuities, and multi-physics. Multiphase flow simulations with SPH methods have been reported abundantly and the specific implementations are much different. In this review, the basic SPH method and issues about fluid pressure, surface tension and solid boundary are discussed. And various implementations of SPH for multiphase flow simulation are mainly summarized as: (1) Lagrangian solver for the two-fluid model (TFM): The two phases are discreterized into two independent groups of SPH particles and coupled by the explicit interphase interaction; (2) multiphase SPH: The multiphase SPH method is considered as the natural extension of SPH method on multiphase flow simulation, and the interphase interaction is implicitly described by SPH parameters; (3) coupling of SPH and other discrete methods: The two phases with large differences each adopt different discrete methods to give play to the advantages of different Lagrangian methods; and (4) coupling of SPH and grid-based methods: The grid method handles the simple main-flow to obtain the balance between accuracy and efficiency. Also, some issues associated with SPH simulations of multiphase flows, such as the physicalization of simulation parameters and the improvement of accuracy and efficiency, are suggested as requiring attention.

Preparation of Bauxite/Deionized Water Nanofluid and Experimental Investigation of Its Thermophysical Properties

In this study, bauxite/deionized water nanofluid was prepared by two-step method and its thermopyhsical properties were experimentally investigated. Bauxite was milled by high-energy spex-type ball milling attritor. Bauxite nanoparticles with a size of 38 nm (2% by weight) and Sodium Dodecyl Benzene Sulfonate (0.5% by weight) were doped into the deionized water while preparing the bauxite nanofluid. Ultrasonication was applied for three hours to obtain stable colloidal dispersions of nanoparticles. It has been seen that the thermal characteristics of bauxite nanofluid was better than that of deionized water. The bauxite nanofluid has the lower surface tension and smaller contact angle than that of base fluid. However, the thermal conductivity and the specific heat of bauxite nanofluid increased by 8.47% and 4.4% compared to deionized water, respectively.

Influence of surface tension on the characteristics of FTIR spectra on the example of saliva

The aim of this work was to test the hypothesis about the effect of surface tension of biological fluids on the characteristics of IR spectra using saliva as an example. The study involved 100 volunteers without clinically significant diseases. Saliva samples were collected from all participants, a parallel determination of surface tension, biochemical composition was carried out, and IR spectra were obtained. Comparison of the results was carried out using cluster analysis, principal component analysis and correlation analysis. The existence of a relationship between the characteristics of absorption bands in IR spectra and surface tension has been established using saliva as an example. It is shown that, first, a change in the surface tension affects the shift of the absorption bands in the spectra, while the intensity and area of ​​the corresponding absorption bands change to a lesser extent. Combinations of the characteristics of the IR spectra have been revealed that provide the maximum correlation relationship with both the total volumetric content of surfactants and their adsorption activity. Correlations with total surfactant content include absorption band characteristics corresponding to proteins, lipids and phospholipids. Whereas the adsorption activity of surfactants correlates mainly with the absorption bands of proteins in saliva. The revealed patterns are substantiated taking into account the biochemical composition of saliva, depending on the surface tension.

On an averaged model for immiscible two‐phase flow with surface tension and dynamic contact angle in a thin strip

AbstractWe consider a model for the flow of two immiscible fluids in a two‐dimensional thin strip of varying width. This represents an idealization of a pore in a porous medium. The interface separating the fluids forms a freely moving interface in contact with the wall and is driven by the fluid flow and surface tension. The contact‐line model incorporates Navier‐slip boundary conditions and a dynamic and possibly hysteretic contact angle law. We assume a scale separation between the typical width and the length of the thin strip. Based on asymptotic expansions, we derive effective models for the two‐phase flow. These models form a system of differential algebraic equations for the interface position and the total flux. The result is Darcy‐type equations for the flow, combined with a capillary pressure–saturation relationship involving dynamic effects. Finally, we provide some numerical examples to show the effect of a varying wall width, of the viscosity ratio, of the slip boundary condition as well as of having a dynamic contact angle law.