High Viscous Liquid Research Articles

The Flow Phenomena of Gas-liquid Two-phase Flow with High Viscous Liquid in a Microchannel

In this work, the effects of liquid viscosity on flow patterns, gas slug velocity and gas slug length in a horizontal circular microchannel with an inner diameter of 530 μm have been investigated by using a high speed camera. As the working fluids, nitrogen gas for the gas and aqueous solutions of glycerol with high viscosities the concentrations up to 78.0 wt% for the liquid were used. Kinematic viscosities and surface tensions of liquids were respectively ranging from twice to 35 times and from 0.9 to 1.0 than that of distilled water. The superficial gas velocities, jG, were ranged from 0.01 to 13.0 m/s, and the superficial liquid velocities, jL, were from 0.05 to 0.30 m/s. The flow patterns observed were slug flow and disturbed ring film flow. The velocity of gas slug for the system of nitrogen-distilled water two-phase flow coincided well with that in case of homogeneous flow, on the other hand, velocities in the case of glycerol solution with the higher viscosities showed the higher values than equation of homogenous flow and equation proposed by Hughmark. The correlation of the distribution parameters, C0, of two-phase flow were proposed in the present paper as a function of the ratio of kinematic viscosity of the liquid to that in distilled water. The tendency was observed that the lengths of gas slug became short when the viscosities of the liquid were increased.

Solidification Behaviour of Al–SiC Composite Foam

This paper describes the solidification behaviour of Al composite melt in the narrow cell wall region in Al foam. Aluminium alloy foams prepared through melt route essentially involve entrapment of gaseous phase in a high viscous liquid followed by solidification. During solidification, the composite melt present in the narrow channel amongst the gas bubbles largely restricts the flow of heat and composite melt solidifies in a restricted region covered by almost zero conducting phases. The solidification front velocity has been computed using different models and their results have been compared. The distribution of SiC particles and matrix microstructure has been evaluated and compared with the experimental observation. It is noted that the solidification front velocity is slowed down due to the presence of gas bubbles and solidification is expected to initiate within the melt away from the melt/bubble interface which facilitates pushing SiC particles towards the gas bubble/melt interface.

Novel coating system on poly(ethylene terephthalate) fabrics with mechanically durable liquid-repellence: Application as flexible materials with striking loading capacity

Construction of the superamphiphobic materials and their application is of particular interest both in academia and industrial circles for years. Herein, a novel coating system for fabricating superamphiphobic poly(ethylene terephthalate) (PET) fabrics was reported based on both aminopropyltriethoxysilane (APTES) and environment-friendly perfluorooctyltriethoxysilane (FAS) co-modified SiO2 nano-particles, 3-Hydroxytyramine hydrochloride (Dopamine), amino-terminated silicone oils and etched PET fabrics via the one-step Schiff-base reaction and Michael addition reaction. The prepared fabrics displayed superamphiphobic properties, with contact angles of various liquids approaching 150°. In addition, the mechanical durability superamphiphobic fabrics were obtained, which were able to withstand 500 cycles of abrasion test, 20 cycles of sand abrasion test or 20 times standard washing. Furthermore, various liquids, including water and high viscous liquids, can easily slide off the surface of the obtained fabrics in a short time at a small angle. The prepared fabric can not only float on water or oil, but also hold up 25.7 times its own body weight things floated on water or 9 times on sesame oil without sinking. This novel and effective coating system can have more potential applications in the development of soft micro-devices working on liquid surfaces, especially on highly viscous liquid surfaces or under the environment with harsh conditions.

Formation of fluid structures due to jet-jet and jet-sheet interactions

The main focus of the present work is to investigate the collision of two oblique cylindrical water jets through a series of experiments. Different regimes for the collision of water jets are illustrated and transitions to the fingering instability and subsequently to the violent flapping regime are discussed. The collision between high inertia and low viscous liquid jets is often used for generating liquid sheets which atomize to form droplets. They are mainly used in the combustion chambers of rocket engines involving liquid fuels having viscosity of the order similar to water. Further, inertia-based asymmetry is studied and an analytical method is proposed (L1 error norm = 0.05) to understand the deflection observed in the plane of sheet formation. The resultant sheets formed are also compared with those generated by the collision of symmetric jets. The range of dimensionless numbers targeted in this study are within 10⩽We⩽1200, 1.5⩽Fr⩽18.5 and 1900⩽Re⩽20,000. We have also illustrated the life cycle of a single sheet in the low inertial regime to form chain-like structures. At last, a different method of generation of multiple interconnected sheets is demonstrated through the distortion of a sheet by the impact of a liquid jet.

Spontaneous Synchronization of Beating Cilia: An Experimental Proof Using Vision-Based Control

This article investigates the formation of spontaneous coordination in a row of flexible 2D flaps (artificial cilia) in a chamber filled with a high viscous liquid (Re = 0.12). Each flap is driven individually to oscillate by a rotary motor with the root of the flap attached to its spindle axle. A computer-vision control loop tracks the flap tips online and toggles the axle rotation direction when the tips reach a pre-defined maximum excursion. This is a vision-controlled implementation of the so-called “geometric clutch” hypothesis. When running the control loop with the flaps in an inviscid reference situation (air), they remain in their individual phases for a long term. Then, the flaps are studied in the chamber filled with a highly viscous liquid, and the same control loop is started. The flexible flaps now undergo bending due to hydrodynamic coupling and come, after a maximum of 15 beats, into a synchronous metachronal coordination. The study proves in a macroscopic lab experiment that viscous coupling is sufficient to achieve spontaneous synchronization, even for a symmetric cilia shape and beat pattern.

Spray performance and steadiness of an effervescent atomizer and an air-core-liquid-ring atomizer for application in spray drying processes of highly concentrated feeds

Atomization for spray drying of high viscous feed liquids is still a challenging task. For this reason, we investigated the potential of two internal mixing pneumatic atomizers, namely an effervescent atomizer (EA) and an Air-Core-Liquid-Ring (ACLR) atomizer. Both atomizers are characterized by a two-phase flow in the exit orifice. While this can be either a two-phase plug or annular flow in case of the EA geometry, the ACLR atomizer enforces annular flow conditions. In this study, spraying experiments were conducted at liquid viscosities between 0.12 and 0.69 Pa∙s. The investigations were performed at a constant liquid flow rate of 20 L/h and gas pressures from 0.3 to 0.9 MPa. Besides the commonly used correlation between Gas-to-Liquid-Ratio (GLR) and time-averaged Sauter mean diameters (SMD¯), we analyzed in-depth the time dependent fluctuation of SMDs, as steady atomization is crucial for spray drying applications. We can conclude that due to strong fluctuations of the SMDs the EA is not suitable for the aimed application in spray drying of high viscous feed liquids. In contrast, the ACLR atomizer is a very promising nozzle for spray drying applications as it delivers much better performance and steadiness also at high liquid viscosities.

Development of Resin Material from Cyclic–Ketones for Coating Applications

Polymerization of cyclic ketones such as cyclopentanone and cyclohexanone was carried out in a batch reactor to develop a synthetic resin. The effect of reaction time, temperature, alkali concentration, and cyclopentanone-to-cyclohexanone weight ratio on various physico–chemical properties, such as, physical state, hydroxyl value, iodine value, viscosity, average molecular weight, and solubility of the resin products was investigated in the present study. Reaction time was varied from 10 to 20 hrs, temperature was varied from 135 to 155 °C, and alkali–to–ketone weight ratio was varied in the range between 0.15 and 0.35. It was observed that the physical state of the products changes from high–viscous liquid to solid state with the increase of temperature, time, and alkali concentration. Hydroxyl value of the products increased with the increase of reaction time, temperature and alkali concentration. However, the solubility of the resins in turpentine oil decreased with the increase of temperature and alkali concentration.

The dynamics of milk droplet\u2013droplet collisions

Spray drying is an important industrial process to produce powdered milk, in which concentrated milk is atomized into small droplets and dried with hot gas. The characteristics of the produced milk powder are largely affected by agglomeration, combination of dry and partially dry particles, which in turn depends on the outcome of a collision between droplets. The high total solids (TS) content and the presence of milk proteins cause a relatively high viscosity of the fed milk concentrates, which is expected to largely influence the collision outcomes of drops inside the spray. It is therefore of paramount importance to predict and control the outcomes of binary droplet collisions. Only a few studies report on droplet collisions of high viscous liquids and no work is available on droplet collisions of milk concentrates. The current study therefore aims to obtain insight into the effect of viscosity on the outcome of binary collisions between droplets of milk concentrates. To cover a wide range of viscosity values, three milk concentrates (20, 30 and 46% TS content) are investigated. An experimental set-up is used to generate two colliding droplet streams with consistent droplet size and spacing. A high-speed camera is used to record the trajectories of the droplets. The recordings are processed by Droplet Image Analysis in MATLAB to determine the relative velocities and the impact geometries for each individual collision. The collision outcomes are presented in a regime map dependent on the dimensionless impact parameter and Weber (We) number. The Ohnesorge (Oh) number is introduced to describe the effect of viscosity from one liquid to another and is maintained constant for each regime map by using a constant droplet diameter (dsim 700 upmu hbox {m}). In this work, a phenomenological model is proposed to describe the boundaries demarcating the coalescence-separation regimes. The collision dynamics and outcome of milk concentrates are compared with aqueous glycerol solutions experiments. While milk concentrates have complex chemical composition and rheology, glycerol solutions are Newtonian fluids and therefore easy to characterize. The collision morphologies of glycerol solutions and milk concentrates are similar, and the regime maps can be described by the same phenomenological model developed in this work. The regime of bouncing, however, was not observed for any of the milk concentrates.

Performance and Emission Analysis of a Ci Engine Fuelled with JOME-JOEE-Diesel Blends

In this study a high viscous liquid fuel, approximately 20 times more than that of diesel, produced from non- edible oil seed jatropha curcaswhich has been considered as an alternative fuel for the compression ignition engine is reduced through trans-esterification process. During this process, the raw jatropha curcas oil is preheated to 60°C and treated with methanol 20% by volume along with potassium hydroxide (KOH) by 0.568% of the oil weight as alkaline catalyst at 60°C reaction temp to produce Methyl Esters of Jatropha Oil (JOME). Similarly, the above method is followed to produce Ethyl Esters of Jatropha Oil (JOEE) with preheating at 70°C. In addition, 2% glycerol is added to the mixture to improve the reaction rate. The lower viscous fuel biodiesel (JOME and JOEE) produced by trans-esterifying of jatropha oil is blended with pure diesel 50% by volume. An experimental investigation have been carried out without altering the CI engine to examine the performance parameters in terms of brake thermal efficiency, total fuel consumption and brake specific fuel consumption for several engine load from 0 Kg to 8 Kg. The study also includes, separation of crude biodiesel from glycerol, washing of crude biodiesel, examination of calorific value using bomb calorimeter, viscosity measurement using redwood and brookfield viscometer, engine emission test and cost comparison for production of one litre of JOME and JOEE. It is inferred from the above study that the blends of JOME with diesel have closer performance to diesel when compared to the blend of JOEE with diesel. But, on comparison of their exhaust emission, the JOEE showed reasonable lower exhaust emission CO and NOx in spite of its higher calorific value when compared with JOME. The study also revealed that the biodiesel can be adopted as an alternative fuel for existing diesel engine without any modification.

Evaluation of fuel consumption and vibration characteristic of a compression ignition engine fuelled with high viscosity biodiesel and hydrogen addition

Viscosity property of a fuel is a crucial point for internal combustion engine characteristics. Performance and emission parameters as well as injector's life of an engine is primarily effected by viscosity of the fuels. In present study, effect of high viscosity biodiesel fuels with hydrogen addition was investigated in a compression ignition engine. Biodiesels that are produced from Pongamia Pinnata and Tung oils were used as pure biodiesels as well as blended with low sulphur diesel fuel at the volume ratios of 50% and 75%. Furthermore, hydrogen gas was injected into intake manifold in order to evaluate its effect with the usage of high viscous liquid fuels. The results revealed that brake specific fuel consumption was increased with biodiesel fuels, whereas hydrogen addition into intake manifold improved the consumption. Total vibration acceleration of the engine reduced with biodiesel and hydrogen additions. Frequency spectrum indicated that this decrement was primarily lowered due to less energy transmitted through engine pistons that converted from chemical energy of fuels.

Experimental Investigation on Near-dry EDM using Glycerin-Air Mixture as Dielectric Medium

Near-dry electrical discharge machining (EDM) is an eco-friendly variant of conventional EDM. This article presents, an experimental investigation on near-dry EDM with high viscous liquid glycerin and air mixture as dielectric medium. In this study, face centered central composite design (CCD) had used to plan the experiments. Response surface methodology (RSM) was applied for proposing the mathematical model. The mathematical model was proposed to determine the significant effect of input parameters on response characteristic. In this investigation, input parameters used for experimentations were current, duty factor flushing pressure and lift. The response characteristic was measured in terms of material removal rate (MRR). Analysis of the results revealed that, all the input parameters were significant for MRR. It was observed that glycerin-air dielectric medium produced higher MRR than water-air dielectric medium at same parametric setting.

Effects of Skill Teaching of Oral Administration for Caregivers of Hospitalized Toddler on Dose Loss and Administration Behavior

Purpose: This study was designed to assess the effects of skill teaching of oral liquid medication on the dose loss and administering behavior. Methods: A nonequivalent control group no-synchronized design was used. 104 participants were assigned to one of two groups. A intervention group received a skill teaching and the control group received the conventional teaching about oral medication. Results: The mean amount of the dose loss by all participating caregivers was 23.3% of the prescribed dose and 61.5% of the caregivers showed dose loss more than 20% of the prescribed dose. Caregivers age (Exp=3.56, p=.017) and time taken for administration (Exp=7.97, p<.001) were related to more dose loss. Toddlers posture sitting in a stroller upon medication (Exp=.14, p=.009) and re-administering the remains after checking the medication bottle (Exp=.22, p=.040) influenced on reduction in dose loss. Before and after the skill teaching, a significant decrease in the dose loss was found in the high-viscous liquid medication only (t=-4.95, p<.001). The difference in the dose loss between the two groups were significant in the high-viscous liquid medication (t=4.95, p<.001). Also, administration behavior were significantly improved in the intervention group. Conclusion: The findings of this study showed that the skill teaching of oral liquid medication designed for toddlers caregivers was effective in reduction of dose loss and improvement in administering behaviors with confidence.

Using biodiesel as a green solvent in the polymerization reactions: the attempt to separate the biodiesel from the polymer by thermal treatment

In this work, the products of the polymerization reaction of epoxidized methyl esters with phthalic anhydride catalyzed by 2-methyl-imidazole, in the presence of biodiesel as a green solvent, were evaluated. The presence of biodiesel enabled reaction at 180 °C during 40 min in a system with good thermal conductivity, homogeneous conditions, and products with physical aspect varying from rubber to high viscous liquid. The products include polyesters, with and without biodiesel, were characterized by: DSC—Differential Scanning Calorimetry, TGA—thermogravimetric analysis, and TGA/MS -TGA coupled to Mass Spectrometer, swelling tests, plane strain compression, and morphological analysis using scanning electronic microscopy (SEM). Considering that biodiesel presents a temperature degradation around 215 °C and the polyesters around 320 °C, a simple thermal treatment was introduced to separate the solvent biodiesel from the reaction products. This treatment includes heating until 250 °C and consequent cooling to the room temperature. The second heating, up to 500 °C, was used to prove, through TGA/MS, that the thermal treatment (heating until 250 °C) not affected the polyester matrix and is sufficient to remove biodiesel.

Positional stability and radial dynamics of sonoluminescent bubbles under bi-harmonic driving: Effect of the high-frequency component and its relative phase

The use of bi-frequency driving in sonoluminescence has proved to be an effective way to avoid the spatial instability (pseudo-orbits) developed by bubbles in systems with high viscous liquids like sulfuric or phosphoric acids. In this work, we present extensive experimental and numerical evidence in order to assess the effect of the high frequency component (PAcHF) of a bi-harmonic acoustic pressure field on the dynamic of sonoluminescent bubbles in an aqueous solution of sulfuric acid. The present study is mainly focused on the role of the harmonic frequency (Nf0) and the relative phase between the two frequency components (φb) of the acoustic field on the spatial, positional and diffusive stability of the bubbles. The results presented in this work were analyzed by means of three different approaches. First, we discussed some qualitative considerations about the changes observed in the radial dynamics, and the stability of similar bubbles under distinct bi-harmonic drivings. Later, we have investigated, through a series of numerical simulations, how the use of high frequency harmonic components of different order N, affects the positional stability of the SL bubbles. Furthermore, the influence of φb in their radius temporal evolution is systematically explored for harmonics ranging from the second to the fifteenth harmonic (N=2–15). Finally, a multivariate analysis based on the covariance method is performed to study the dependences among the parameters characterizing the SL bubble. Both experimental and numerical results indicate that the impact of PAcHF on the positional instability and the radial dynamics turns to be progressively negligible as the order of the high frequency harmonic component grows (i.e. N≫1), however its effectiveness on the reduction of the spatial instability remains unaltered or even improved.

Synthesis of Polymerizable Ionic Liquid Monomer and Its Characterization

The polymerizable monomer of 1-(6-hydroxyhexyl)-3-methylimiadazolium bromide ionic liquid (IL) was synthesized. The thin layer chromatography tests were conducted at each step to verify the reactions. It was observed that the ionic liquid compound formed after 48 hours though confirmed the presence of starting materials. A high viscous transparent liquid was extracted and believed to be formed of 99% yielding of ionic liquid. Apart from that, the synthesis of ionic liquid was also performed using microwave treatment and heating to stimulate the reaction. Surprisingly, it was observed that the reaction was taking place within a fraction of second when the synthesis process was conducted with microwave treatment. In the second step, esterification IL with methacryloyl chloride was done to obtain monomer of polymerizable ionic liquid (m-PIL). The final product was a high viscous yellowish liquid.

Using Quartz Crystal Microbalance for Field Measurement of Liquid Viscosities

The field measurement of liquid viscosities, especially the high viscous liquids, is challenging and often requires expensive equipment, long processing time, and lots of reagent. We use quartz crystal microbalances (QCMs) operating in solution which are also sensitive to the viscosity and density of the contacting solution. QCMs are typically investigated for sensor applications in which one surface of QCM completely immersed in Newtonian liquid, but the viscous damping in liquids would cause not only large frequency shifts but also large losses in the quality factorQleading to instability and even cessation of oscillation. A novel mass-sensitivity-based method for field measurement of liquid viscosities using a QCM is demonstrated in this paper and a model describing the influence of the liquid properties on the oscillation frequency is established as well. Two groups of verified experiments were performed and the experimental results show that the presented method is effective and possesses potential applications.

Tackling the challenges in modelling entrained-flow gasification of low-grade feedstock

Development of a new technology for conversion of residual biomass into a liquid fuel via pyrolysis–gasification–gas cleaning–synthesis is the overall objective of the on-going bioliq® project. The present paper gives an overview on research activities dedicated to mathematical modelling of entrained-flow gasification for conversion of biomass-based suspension fuels into a medium calorific (LCV around 15 MJ/kg) synthesis gas. The objective is to identify knowledge gaps that currently prohibit a knowledge-based mathematical description of reacting high-pressure multi-phase flows so as to model the bioliq® gasification reactor in particular and biomass conversion in entrained flow gasifiers in general. Substantial knowledge gaps for high pressure process conditions have been identified for atomization of high viscous liquids, gasification chemistry for biomass-based fuels, radiative heat transfer as well as slag formation mechanisms. The paper proposes an interdisciplinary research approach in a holistic manner to close these gaps.

Effect of the Polymer Composition on the Physicochemical Properties of Microencapsulated Fish Oil Using Spray Drying

In this study, the effect of polymer composition on physicochemical characteristics of fish oil microcapsules produced by spray drying (180 °C) was investigated. Fish oil powders were produced using hydroxy propyl methyl cellulose (HPMC) 15 cP and HPMC 5 cP as a solid carrier and PEG 6000 as a plasticizer. The ratio of the polymer to the lipid phase influenced the reconstitution properties. Initially, it was difficult to atomize the high viscous liquid like oil-water (o/w) emulsion because HPMC itself is a very viscous polymer; however, the particle sizes of less than 60 µm were produced. Scanning electron microscopy and the amount of extracted oil from the surface revealed that HPMC 15 cP provided the highest protective and prolonged effect on the covering of fish oil. The wettability and particle density of the powder was very suitable, which improve the flow ability of the powders. All the indices of powders such as surface oil, microencapsulation efficiency and surface morphology prepared from HPMC 15...

Nanocomposite polymer carbon-black coating for triggering pyro-electrohydrodynamic inkjet printing

The pyro-electrohydrodynamic (EHD) manipulation of liquids has been discovered and demonstrated recently as a high resolution printing technique avoiding the use of nozzles and external electrodes. The activation of the pyro-electric effect is usually achieved on ferroelectric crystals by an external heating source or by an infrared laser. Here, we show an original modality for triggering the pyro-EHD process through a light-absorbing polymer nanocomposite thin layer deposited on the ferroelectric substrate, thus overcoming some limitations of the previous configuration. Significant simplification and compactness of the set-up is achieved thanks to the nanocomposite coating, since a commercial low-cost white-light halogen lamp can be adopted to trigger the pyro-jetting process from a liquid reservoir. Remarkably, high resolution is achieved in dispensing very high viscous liquids. Practical demonstrations in polymer optical microlenses direct printing using polydimethylsiloxane and poly(methyl methacrylate) are finally reported to validate the approach in handling high-viscous polymers for practical applications.

Dynamic nuclear polarization properties of nitroxyl radical in high viscous liquid using Overhauser-enhanced Magnetic Resonance Imaging (OMRI)

The dynamic nuclear polarization (DNP) studies were carried out for 15N labeled carbamoyl-PROXYL in pure water and pure water/glycerol mixtures of different viscosities (1.8cP, 7cP and 14cP). The dependence of DNP parameters was demonstrated over a range of agent concentration, viscosities, RF power levels and ESR irradiation time. DNP spectra were also recorded for 2mM concentration of 15N labeled carbamoyl-PROXYL in pure water and pure water/glycerol mixtures of different viscosities. The DNP factors were measured as a function of ESR irradiation time, which increases linearly up to 2mM agent concentration in pure water and pure water/glycerol mixtures of different viscosities. The DNP factor started declining in the higher concentration region (∼3mM), which is due to the ESR line width broadening. The water proton spin–lattice relaxation time was measured at very low Zeeman field (14.529mT). The increased DNP factor (35%) was observed for solvent 2 (η=1.8cP) compared with solvent 1 (η=1cP). The increase in the DNP factor was brought about by the shortening of water proton spin–lattice relaxation time of solvent 2. The decreased DNP factors (30% and 53%) were observed for solvent 3 (η=7cP) and solvent 4 (η=14cP) compared with solvent 2, which is mainly due to the low value of coupling parameter in high viscous liquid samples. The longitudinal relaxivity, leakage factor and coupling parameter were estimated. The coupling parameter values reveal that the dipolar interaction as the major mechanism. The longitudinal relaxivity increases with the increasing viscosity of pure water/glycerol mixtures. The leakage factor showed an asymptotic increase with the increasing agent concentration. It is envisaged that the results reported here may provide guidelines for the design of new viscosity prone nitroxyl radicals, suited to the biological applications of DNP.