High-viscosity Liquid Research Articles

Low viscosity liquid bridges: Stretching of liquid bridges immersed in a higher viscosity liquid

Low viscosity liquid bridges: Stretching of liquid bridges immersed in a higher viscosity liquid

Investigation on High-Viscosity Chemical Waste Liquid Atomizer Based on VOF-DPM

The viscosity of adiponitrile waste liquid is as high as 1000 cp. It is challenging to spray and atomize the waste liquid normally. Based on the coaxial three-channel pneumatic atomizer, a two-stage supersonic steam atomizer is proposed in this paper, and the atomization process is simulated by Fluent software. Compared with the traditional atomization simulation method, the Volume-of-Fluid to Discrete-Phase-Model (VOF-DPM) bi-directional coupling model and Adaptive Mesh Refinement (AMR) technology can save mesh and improve the computational efficiency. The atomization processes of primary breakup and secondary breakup are entirely captured and analyzed. The results show that the Sauter Mean Diameter (SMD) is about 116–180 μm, the SMD decreases with the increase of steam inlet absolute pressure, and the atomization quality can meet the combustion requirements. This study can be used for the performance optimization of the high-viscosity liquid atomizers in the chemical and aerospace industry and shorten the time engineers spend in the simulation calculation to verify the rationality of the structure.

CFD simulation of a small bubble motion in 3D flow domain: effect of liquid density, viscosity and surface tension

The motion of spherical and slightly deformed bubbles rising rectilinearly in a stagnant liquid was numerically simulated in a fully three-dimensional domain using the CFD solver COMSOL Multiphysics. The interface was tracked by the built-in conservative Level set method on a fixed numerical grid. The purpose of this work was to study the single bubble motion in three industrially used liquids that differ significantly in surface tension, density, and viscosity. The motion of bubbles with diameters up to 1.6 mm was also studied experimentally using a high-speed camera. The data obtained together with the results of theoretical models for bubble motion were used for the validation of the simulation data. Using a 3D domain, very good agreement was obtained in both bubble shape deformations and bubble terminal velocity. The best results were achieved for propanol with low surface tension and low viscosity. In the case of high surface tension and low viscosity liquid (water), both the bubble deformation and the bubble velocity were slightly underestimated. In the case of glycerol (high surface tension and viscosity), the negligible bubble deformation is correctly calculated, but the velocity is again slightly underestimated.Graphical abstract

Lysine‐Based Ionic Liquid Enables Peptides to Reverse Skin Photoaging: From Leaves to Roots

AbstractPeptides and proteins are pharmacologically active and highly safe; however, their local delivery remains a challenge in the field of drug delivery. Based on this, a novel lysine‐based ionic liquid via proton transfer between lysine and malic acid that can overcome the difficulties in the application of copper peptides is developed. Density functional theory, molecular docking simulations, and experimental validation demonstrate the chemical stability of this ionic liquid. Furthermore, by combining it with a vegetable oil system, a biocompatible lysine‐based ionic liquid microemulsion system is constructed, which perfectly combines the high viscosity of ionic liquids and low viscosity of microemulsions. Multi‐dimensional analysis shows that the system not only leads to a dramatic elevation in the local penetration of copper peptides, but also enables copper peptides to effectively suppress skin aging. In addition, transcriptome sequencing analysis reveals that the system primarily regulates p53, p16, and ECM‐related signaling pathways to combat photoaging in the skin. Overall, a noninvasive, efficient, and convenient anti‐aging system with enormous potential is developed for the clinical prevention and treatment of skin photoaging.

Impingement and breakup characteristics of free opposed impinging jets with unequal nozzle diameter

The free opposed impinging jets with unequal nozzle diameter is developed to improve mixing efficiency at unequal flowrates for liquid–liquid reactions. The liquid sheet breakup characteristics and droplet behavior are investigated using particle image velocimetry. Water, 40w% glycerol-water (40G), and 50% glycerol-water (50G) under different jet velocities and nozzle diameters are studied for comparison, the correlation equations are obtained and the errors are analyzed. When the jet velocity increases, the liquid sheet breakup mode exhibited a closed-rim mode, open-rim mode, rimless mode, wave or ligament mode, and fully developed mode for water and 40G under a nozzle diameter of 1.5–2 mm, and the first four modes were observed with the high viscosity liquid (50G) or under a large nozzle diameter (2–3 mm). As the jet velocity increases, the dimensionless breakup length increases sharply at the closed-rim and open-rim modes, and then decreases at the rimless mode. The sheet thickness, Sauter mean diameter, average droplet diameter, and droplet velocity decrease, and the droplet size becomes more uniform with increasing jet velocity. However, the opposite variation trend is observed with increasing viscosity and nozzle diameter, and the effect is more significant at u < 4.25 m/s. The droplet average diameter increases at u = 2.12 m/s and 3.18 m/s and decreases at u ≥ 4.25 m/s downwards along y-axis due to the coalescence and secondary breakup of droplets. The droplet velocity becomes lower as droplets move downwards along y-axis from −40 mm to −50 mm due to the dissipation of momentum. The results reveal that the increase of viscosity and nozzle diameter has a negative effect on liquid sheet and droplet behavior at low jet velocities. The rimless mode is the key mode affecting the transition of the sheet breakup mechanism, and after this mode, the negative effects of viscosity and nozzle diameter weaken due to the high momentum, which promotes the breakup of the liquid sheet and droplets. It will provide theoretical support for the mixing mechanism with unequal flowrates, and is helpful to expand the application of free opposed impinging jets.

Collision regimes and dynamic behaviors of a viscous droplet impacting on a spherical particle at high temperatures

Understanding droplet–particle collision behaviors is essential for the pyrohydrolysis process of pickling liquor, where the pickling liquor is sprayed and dried into particles. This study systematically investigated the collision characteristics between a viscous droplet and a heated stainless steel particle whose temperature ranged from 100 to 700 °C. The results indicate that the vapor thrust promotes droplet rebound in smaller spreading diameters but induces disintegration in larger spreading diameters under the film boiling regime. The collision regime map is summarized, and the transition thresholds of collision patterns are significantly increased with increasing liquid viscosity. The spreading factor and contact line velocity are strongly affected by the particle temperature at high liquid viscosities. In addition, the hydrophobic nature of particle surface in film boiling regime is favorable for droplet spreading. The dynamic contact angle significantly depends on the particle temperature and droplet properties. The dimensionless contact time shows a power law dependency on the Weber number in the rebound pattern, but it is almost a constant in the disintegration pattern.

Selecting adhesive molecular layers with matched surface free energy and chemisorption for shape-fixed UV-cured thin films fabricated by laser-drilled screen printing and UV nanoimprinting

This study investigates the importance of surface free energy and chemisorption of substrates for the formation of a UV-cured thin film corresponding to a residual layer in UV nanoimprint lithography. Silicon substrate surfaces were modified with binary molecular layers which were prepared through photo-oxidation of a monomer-repelling monolayer and implantation of a reactive surface modifier with an acrylate polymerizable group. Laser-drilled screen printing enabled the placement of droplets of high-viscosity dimethacrylate UV-curable liquid on the modified substrates. UV nanoimprinting with a modified flat mold surface allowed the formation of UV-cured films with a square shape and a sub-100 nm thickness. The thickness of the UV-cured film was tuned precisely in the case of the substrate showing almost the same surface free energy value as the mold surface. The comparison with and without the reactive surface modifier revealed that the chemisorption was essential for the film formation on the substrates.

The macrosegregation behaviour of Fe-C-Cr-Mo type steel in laboratory scale model ingot.

In ingot casting, it is important to predict and control segregation and casting defects that occur during the solidification process, because they have a significant effect on the quality of the steel ingot. In some special steels, in typical Fe-C-Cr-Mo type high carbon tool steels, macro-segregation tends to be more pronounced due to their wide solid-liquid coexistence temperature range and molten steel properties such as relatively higher liquid viscosity than basic carbon steels. In order to investigate segregation and defect formation phenomena during solidification, many experiments have been conducted using specially designed laboratory scale model ingots that can induce partial difference of solidification to cause macrosegregation phenomena. However, these kind of experimental approaches for special steels are less conducted and influence of alloy types on the macrosegregation behaviour is still not well understood. In this study, a model ingot which have a steel chill ring in the middle region of a mullite mold was prepared, then Fe-0.45C(mass%) carbon steel, Fe-1C-1.8Cr(mass%) bearing steel and Fe-1C-8Cr-2Mo(mass%) high carbon tool steel were cast into 30kg ingots and the macrosegregation behaviour was investigated.

Response Law of Series Resonant Resistance under the Droplet Model of Quartz Crystal Microbalance

Liquid viscosity measurement, especially the accurate detection of high-viscosity liquid, has been a hot research in biomedical, petrochemical, and other industries. In this article, a series resonant resistance response of quartz crystal microbalance (QCM) under the droplet model is introduced to characterize the density and viscosity of the liquid. The experimental results of water, glycerol solution with 50% water content, and pure glycerol show that the resonant resistance has a similar response to the resonant frequency and higher stability. Compared with the traditional method in which QCM contacts liquid on one side, this new method has the advantages of extremely high-quality factor, wide measurement range, and minimal reagent requirement, which has important guiding significance for the application of QCM in high-viscosity liquids.

Prediction of slug length for high-viscosity oil in gas/liquid horizontal and slightly inclined pipe flows

The production and transportation of high viscosity liquid/gas two-phase Newtonian mixtures along petroleum production systems is a challenging operation due to the lack of understanding the flow behavior and characteristics. In particular, accurate prediction of two-phase slug length in pipes is crucial to efficiently operate and safely design oil well and separation facilities. The objective of this study is to develop a mechanistic model to predict high viscosity liquid slug length in pipelines and to optimize the proper set of closure relationships required to ensure high accuracy prediction. A large high viscosity liquid slug length database is collected and presented in this study, against which the proposed model is validated and compared with other models. A mechanistic slug length model is derived based on the first principles of mass and momentum balances over a two-phase slug unit, which requires a set of closure relationships of other slug characteristics. To select the proper set of closure relationships, a numerical optimization is carried out using a large slug length dataset to minimize the prediction error. Thousands of combinations of various slug flow closure relationships were evaluated to identify the most appropriate relationships for the proposed slug length model under high viscosity slug length condition. Results show that the proposed slug length mechanistic model is applicable for a wide range of liquid viscosities and is sensitive to the selected closure relationships. Results revealed that the optimum closure relationships combination is Archibong-Eso et al. (2018) for slug frequency, Wong (2003) for slug liquid holdup, Jeyachandra et al. (2012) for drift velocity, and Nicklin et al. (1962) for the distribution coefficient. Using the above set of closure relationships, model validation yields 34% absolute average percent error, outperforming all existing slug length models.

CFD Study on the Influence of Liquid Viscosity on the Swirling Gas-Liquid Flow

Swirling two-phase flow is important in industrial mixing and separation systems. In this work, the effect of liquid viscosity was investigated numerically using the Euler-Euler Computational Fluid Dynamics (CFD) model where the liquid and the gas acted as the continuous and dispersed phases, respectively. CFD simulations were performed to model the gas-liquid flow inside a horizontal pipe equipped with a static mixer element with liquid viscosities of 1, 5, 10, and 50 cP. The gas volume fraction contours in the central axial plane show that the evolution of gas distribution is strongly influenced by the liquid viscosity, especially in the region downstream of the element. The calculated results show that the higher the viscosity, the shorter the gas core downstream of the element. Gas separation after the element occurs over a shorter distance with higher liquid viscosity. A possible explanation is that the swirling flow decays faster at higher liquid viscosities, and the buoyancy force dominates over the centrifugal force.

Effect of liquid viscosity on the gas–liquid two phase countercurrent flow in the wellbore of bullheading killing

Studying the gas–liquid two-phase countercurrent flow under high liquid viscosities is key in designing the well-killing parameters of the bullheading method; however, currently, in-depth research on this issue is limited. Herein, using a self-designed vertical visualization wellbore gas–liquid two-phase flow experimental system with a tube diameter of 0.1 m and liquid viscosity in the range of 1–50 mPa s, a simulation experiment of bullheading killing was conducted. The effects of liquid viscosity on the bubble morphology, bubble migration, and gas–liquid countercurrent flow pattern were analyzed, and the mechanism of back pressing of gas during the well-killing process of the bullheading method in a large-scale tube was revealed. Moreover, the influencing factors and variation in the critical displacement of bullheading were analyzed. The results revealed that the stability of Taylor bubbles increased and the number of small bubbles decreased with the increase in liquid viscosity, resulting the gradual shrinkage or disappearance of the churn flow and bubbly flow, expansion of the region of slug flow, and downward movement of the transition boundary between bullet-cup flow and slug flow. On approaching the critical liquid displacement during the process of simulated bullheading, Taylor bubbles rapidly dissociated into small bubbles and turned around during the rising process, forming a gas–liquid downward flow, following which the gas was successfully pressed back. In addition, our analysis revealed that the press-back effect is not always positively correlated with the viscosity of the kill fluid. The critical displacement of the well-killing fluid first decreased and then increased with an increase in the liquid viscosity. Finally, based on the experimental results, an improved calculation method for the critical displacement of bullheading considering the influence of liquid viscosity was established, which could provide important theoretical guidance for the parameter design of bull heading.

Removal of chlorine, microparticles and water from high-viscosity liquids by a sand filter coupling hydrocyclone

Separation energy consumption in industrial production accounts for 10–15 % of global energy consumption. Nonthermal separation represented by sand filtration can open a new door to separation energy savings. Traditional sand filters cannot be regenerated completely, which limits their efficiency. A sand filter coupling hydrocyclone (SFCH) was proposed to enhance regeneration. The performance of SFCHs with different separation particle sizes was systematically analyzed, as indicated by turbidity, water, and chlorine in a pilot-scale experiment. The larger the sand particle size of the SFCH was, the longer it took to reach saturation. The efficiency and cycle were balanced by combining SFCHs with particle sizes of 1–2 mm and 0.5–1 mm. The average turbidity, water and chlorine decreased from 793 NTU, 1439 mg/L, and 126 mg/L to 155 NTU, 389 mg/L, and 88 mg/L, respectively, with a cycle of 88 h. Under the same conditions, the effluent turbidity of the SFCH was half of that of the original disc centrifuge, which indicates that the life of the downstream alumina bed was doubled. Almost 260 t/year alumina consumption can be reduced in a 200,000 tons/year-capacity petroleum resin plant, saving 600,000 USD/year, mainly due to the extension of the service life of the alumina bed.

Movable and Focus-Tunable Lens Based on Electrically Controllable Liquid: A Lattice Boltzmann Study.

Adjusting the focal length by changing the liquid interface of the liquid lens has become a potential method. In this paper, the lattice-Boltzmann-electrodynamic (LB-ED) method is used to numerically investigate the zooming process of a movable and focus-tunable electrowetting-on-dielectrics (EWOD) liquid lens by combining the LBM chemical potential model and the electrodynamic model. The LB method is used to solve the Navier-Stokes equation, and the Poisson-Boltzmann (PB) equation is introduced to solve the electric field distribution. The experimental results are consistent with the theoretical results of the Lippmann-Young equation. Through the simulation of a liquid lens zoom driven by EWOD, it is found that the lens changes from a convex lens to a concave lens with the voltage increases. The focal length change rate in the convex lens stage gradually increases with voltage. In the concave lens stage, the focal length change rate is opposite to that in the convex lens stage. During the zooming process, the low-viscosity liquid exhibits oscillation, and the high-viscosity liquid appears as overdamping. Additionally, methods were proposed to accelerate lens stabilization at low and high viscosities, achieving speed improvements of about 30% and 50%, respectively. Simulations of lens motion at different viscosities demonstrate that higher-viscosity liquids require higher voltages to achieve the same movement speed.

Hydrodynamics and mass transfer performance of gas–liquid microflow in viscous liquids

Mass transfer performance is markedly improved in microchannels compared with traditional gas–liquid chemical devices. The residence time is a crucial parameter for determining the mass transfer performance. However, investigation of the residence time in gas–liquid absorption systems remains insufficient, especially in viscous gas–liquid systems with obvious flow non-uniformity between the two phases. Herein, the microscale gas–liquid flow and mass transfer performance in viscous liquids (9.0–55.4 mPa·s) based on the true residence time are investigated. Owing to the broad operating conditions of the gas–liquid flow ratio (0.2–6.7), both Taylor flow and bubbly flow patterns were observed. The results show that the bubble velocity gradually decreases to the minimum value with increasing flow distance in the Taylor flow pattern owing to gas absorption. Subsequently, bubble velocity gradually increases under the bubbly flow pattern, and the dominant factor of bubble velocity is pointed out. The true bubble residence time initially increases and then gradually decreases compared to the superficial time as the gas holdup decreases, based on the superficial velocity using the initial flow rates. The transition point occurs at a gas holdup of 0.2. In addition, the turning point of the different rules of the pressure drop occurs at a gas holdup of 0.5. Finally, a new dimensionless equation was proposed to predict the mass transfer coefficient and reveal the equation differences between low- and high-viscosity liquids. This work enriches the understanding of microflow characteristics and mass transfer performance in viscous solutions and provides a reliable guide for microreactor design.

SO2 Adsorption and Kinetics Analysis during Supported Triethanolamine Acetate Ionic Liquid Desulfurization.

Ionic liquid desulfurization is an effective method for achieving green and circulating desulfurization. To overcome the negative impact of the high viscosity of ionic liquids on the desulfurization process, an economical and efficient supported ionic liquid-triethanolamine acetate ionic liquid/silica (TAIL/SiO2) was prepared in this study. TAIL is synthesized using triethanolamine and acetic acid and subsequently loaded onto silica gel particles. The effects of the reaction temperature, humidity, silica particle size, and loading ratio on SO2 adsorption are investigated using a fixed-bed reactor. The results indicate that the surface of the silica gel loaded with ionic liquid formed uneven spherical clusters, and the aggregate volume increased with an increase in the loading ratio. The TAIL/SiO2 sulfur capacity could be effectively increased by increasing the loading ratio (exceeding 0.74 is unfavorable), decreasing the silica particle size, and reducing the reaction temperature and moisture content. The maximum sulfur capacity can reach 124.98 mg SO2/(g TAIL/SiO2) under experimental conditions, which is higher than that of activated carbon. The Bangham rate model effectively predicts the kinetics of the adsorption process of SO2.

High strength and rapid solution Mg alloy by adding Fe element fabricated by binder jetting additive manufacturing

The effects of Fe addition on the mechanical properties and corrosion behaviors of AZ91D alloys prepared by binder jetting additive manufacturing have been investigated. The results show that the constitution of the second phase is large dependence on Fe content. With the Fe content increasing, the second phase can transform AlFe phase to Fe and AlFe phase. In addition, with increasing Fe content, the content of second phase increases gradually, while the content of pores also increases. We believe that with the Fe content increasing, the content of second phase with Fe element increases which the melt temperature is higher than sintering temperature, and the content of liquid phase decreases, that leading the high-viscosity liquid alloy cannot fill the pores fully and the more pores will remain and causes the relative density reduces. The compressive strength shows a parabola relationship with Fe content. Furthermore, adding Fe can accelerate the degradation of Mg alloys owing to the galvanic corrosion. The sample with 5 wt% Fe content shows the highest ultimate compressive strength (440 MPa) and fast degradation rate (9091 mm/Y), which meets the soluble Mg alloy with rare earth but cost much lower.

Spray Characterization of a Preheated Bio-Oil Surrogate at Elevated Pressures

Abstract Atomization plays an important role in the gasification or combustion of bio-oils, where the atomizer parameters need to be properly controlled to efficiently atomize a highly viscous liquid at elevated pressures with imparting the least amount of kinetic energy to the discharged droplets because of evaporation and chemical reaction constraints. With a focus on bio-oil deployments in microgas turbines (MGTs), an aqueous surrogate of a preheated bio-oil, injected from an original equipment manufacturer (OEM) twin-fluid atomizer, is used in the present study for spray size and velocity measurements at elevated pressures. The experiments were conducted in High Pressure Spray Facility of the National Research Council of Canada (NRC) using various optical diagnostics including laser sheet imaging (LSI), phase Doppler anemometry (PDA), and laser diffraction (LD). A scaling strategy was adopted to conserve the ranges of gas-to-liquid momentum flux ratio, M, at different working pressures, P. Over the range of conditions studied, it is found out that the cone angle of sprays is insensitive to P, but they decrease with increasing M. For a constant value of M, droplet mean diameters increase and their corresponding velocities decrease with increasing P, attributed to the effect of gas-to-liquid density ratio on the primary breakup of a liquid jet in a coaxial gas stream. Therefore, to estimate the Sauter mean diameter of spray droplets, D32, a correlation previously reported in the literature is modified by including the effect of system air density at elevated pressures, and a novel correlation is proposed based on four dimensionless groups, namely, gas Weber number and gas-to-liquid momentum flux ratio, density ratio, and viscosity ratio. The detailed results obtained in the present study could be used to define the optimal parameters required for twin-fluid atomization of high viscosity liquids with various atomization gases under realistic operating conditions and to enhance the capabilities of their numerical simulations.

A piezoelectric-driven resonant unit for high-viscosity-liquid injection.

In this paper, a piezoelectric-driven resonant unit for high-viscosity-liquid injection is introduced. For high-viscosity-liquid delivery in low voltage and frequency, a vibrating block is fixed under the rectangular piezoelectric actuator, to transport the vibration to the chamber, leading the unit into resonant state. The valveless chamber is designed eccentrically to promote the tendency of positive flow and diminish the backflow. Numerical simulation and analyses are carried out to optimize the chamber design, and the experiments with liquid in different viscosity, radius of the vibrating block, and the influence of gravity are conducted. The unit achieves a fast delivery speed with a relatively high liquid viscosity compared to the similar study, as the highest flow rate of 52.4, 88.4, and 103.9 ml/min at 100V, 60Hz with the liquid of 54.42, 21.13 cP, and water, respectively. The flow rate drops by 40.7%, while the liquid viscosity increases 157.5%.

Hindered Settling of Fiber Particles in Viscous Fluids

In the current literature, information can mainly be found about free and hindered settling of isometric particles in Newtonian and non-Newtonian fluids. These conclusions cannot be used to describe the sedimentation of non-isometric particle in non-Newtonian fluids. For this reason, we have carried out systematic experiments and calculated the correlation of the hindered settling velocity of a cloud of non-isometric particles in high-viscosity and pseudoplastic liquid. The experiments were performed in transparent model fluids, namely, glycerine (a Newtonian fluid) and an aqueous solution of carboxylmethylcelulose CMC (a non-Newtonian pseudo-plastic liquid). These fluids have similar rheological properties, for example, the fresh fine-grained cementitious composites HPC/UHPC. The experiments were carried out with steel fibers with a ratio of d/l = 0.3/20. The settling velocity was determined for fiber volumes from 1% to 5%. While it is known from previous studies that for spherical particles the hindered settling velocity is proportional to the porosity of a suspension cloud on exponent 4.8, which was confirmed by our verification experiment, for the studied fiber particles it is proportional to the porosity on exponent 22.1. This great increase in the exponent is an effect of both the shape of the particles and, in particular, a mutual influence that arises from their interweaving and connection in the suspension.