High Viscous Liquid Research Articles

Drift Flux Model Parameters Estimation based on Numerical Simulation of Slug Flow Regime with High-Viscous Liquids in Pipelines

Multiphase flow models involve more variables than available equations, thus constitutive equations are required to solve the system's governing equations. In the Drift Flux Model, mean drift velocity of the gas phase is estimated by using a Dispersed-Phase Distribution Coefficient and Gas Drift Velocity closure relationships. This study investigates the hydrodynamic of the slug flow regime with high-viscous liquids, and develops an equation for the Distribution Coefficient. Simulation cases were run with inclination angles varying from 0° (horizontal direction) to 90° (vertical upward) and a 0.051m-ID pipe. OpenFOAM, an open-source CFD software, was used to numerically solve the two-phase flow problem. A detailed methodology to estimate drift flux parameters from the data stored at each grid block is presented. This step-by-step methodology allows researchers to further develop the constitutive equations for Distribution Coefficient and the Drift Velocity for other cases. Simulated results were compared with experimental data from the literature and other published models for horizontal and vertical pipes. The results showed that this CFD modeling approach is suitable for representing actual slug flow in pipes. The newly developed Distribution Coefficient constitutive equation has less than 10% absolute average relative error for the viscosity range of 0.14 to 1.120Pa·s, and pipe inclinations from 0° to 90°.

Thermodynamic calculation and microscopic examination of liquid phase formation in MgO–C refractories contain calcium magnesium aluminate

MgO-CMA-C refractories contain calcium magnesium aluminate (CMA) to increase the corrosion and penetration resistance due to the increase of the alumina and lime content of the infiltrating slag leading to a reduced reactivity. It is expected, that the addition of CMA to MgO–C may also result in the in situ formation of a small amount of high viscous liquid phase, which may affect the high-temperature properties. Hence, thermodynamic calculations, as well as EBDS analysis, were performed to gain insight into the effect of CMA on the liquid phase formation in MgO. Thermodynamic calculations identified liquid phase formation even in sintered and fused magnesia without CMA. By adding CMA, the increase in liquid phase portion, especially due to increase in Al2O3 portion, is only marginal (approx. 0.7 wt.-%) and the liquid phase formation is retarded up to 1500 °C. By means of EBSD analysis, an amorphous phase composed of Ca, Fe, P, Al, and Mg within the MgO-CMA matrix could be identified, which also indicates a liquid phase formation and assists the findings of the thermodynamic calculations.

Versatile, mechanochemically robust, sprayed superomniphobic coating enabling low surface tension and high viscous organic liquid bouncing

Superomniphobicity repelling both water and organic liquids is an important feature of special wettability material, which has received great attention in surface/interface area. The bottleneck in the real application is how to develop robust superomniphobic surface by using cost-effective, scalable, facile materials and methods. Here, we report a superomniphobic coating by using low-cost and scalable spraying suspensions method. The sprayed superomniphobic coating assembles into multi-leveled micro/nanostructures with very low apparent surface free energy of 12.98 mN m−1. The coating is capable of diverse organic liquids bouncing with liquid surface tension low to 21 mN m−1 and viscosity high to 297.8 mPa s. Remarkably, the coating can be applied in different substrates due to the in-situ formed adhesive and demonstrates strong mechanical robustness under high pressure water impact (27.8 m s−1), abrasion and tape-peeling cycles, and sustains exposure to highly corrosive aqua regia, extreme low/high temperature and UV environments. The organic liquid bouncing behavior related to impact velocity and liquid properties were also studied. With facile fabrication and multifaceted robustness, our coating paves the way for real industrial applications.

Effect of phase properties on liquid-liquid two-phase flow patterns and pressure drop in serpentine mini geometry

In the present study, a comparative analysis of the flow patterns and pressure drop in a serpentine miniature geometry of inner diameter 2 mm and a serpentine annulus miniature geometry with an effective inner diameter 1.73 mm are carried out. Three pairs of liquids have been considered for this purpose. Four different flow patterns have been observed in serpentine geometry, while only two flow patterns are observed in serpentine annulus geometry. The range of occurrence of flow patterns depends on if the low or high viscous medium liquid surrounds the dispersed phase. The effect of phase properties found to be diminished if a hydrophilic wire is placed inside the serpentine geometry. It enhances slug coalescence and subsequent break-up and leads to the formation of slug droplet and dispersed droplet flow patterns across all the liquid pairs. Further, a unified approach is proposed to estimate the drop in pressure, which shows an acceptable agreement with the experimental results.

New Design of the Falling-Body Rheoviscometer for High and Extra-High Viscous Liquid Measurements. Viscosity of Vacuum Oils

The dynamic viscosities of four high-viscous vacuum oil samples, working liquids (BM-1CM, BM-1CN, LEYBONOL LVO 500, and Alkaren-D24) for diffusion vacuum pumps, have been measured over the temperat...

Effect of rotation on temperature uniformity of microwave processed low - high viscosity liquids: A computational study with experimental validation

Microwave processing of liquid foods is a recent trend with volumetric heating effect compared to conventional processing. A certain temperature non-uniformity is, however, still observed due to non-uniform electric field distribution. This is especially significant in high viscous products due to the difficulty in creating natural convection mixing. Enabling rotational effects to liquid might be an approach to obtain a uniform temperature distribution. Therefore, the objectives were to develop a mathematical model for microwave processing of liquid foods, experimentally validate it and demonstrate rotation on temperature uniformity. A multi-physics finite element program was used for model development, and experimental studies were carried out in a batch system at 2.5 rpm. Validated model was then used to demonstrate the improved temperature uniformity in low - high viscous liquids with rotation (0 to 20 rpm). Considering the recent trend in the use of continuous microwave system for the industrial production, this study is expected to give a certain sight for rotational effects on microwave processing. The experimentally validated model is now to be expanded for further design and optimization studies for industrial scale continuous systems.

Numerical simulation of bubble formation process due to nucleate boiling in a high viscous liquid

Numerical simulation of bubble formation process due to nucleate boiling in a high viscous liquid

“Liquefication” and “Dynamic Separation” Different Aspects of the Same Problem

In 2015 the Bulk Jupiter sank during bad weather loaded with bauxite. Nearly automatically everybody considered “liquefaction” to be the prime cause of this accident. Liquefaction is a phenomenon where solid bulk cargo, triggered by the ship movements, starts to behave has a high density viscous liquid in the holds. The stability is negatively influenced by the free surface effect and further research, especially by the Global Bauxite Working Group or GBWG showed that bauxite ore simply will not liquefy even under the worst case shipping conditions. Evidence from real world shipments of bauxites shows that instabilities due to moisture cannot be explained by liquefaction phenomena, but can be under a “dynamic separation” mechanism of instability. Both liquefaction and dynamic separation are caused by an excessive moisture of the bauxite cargo. However, the influence on the stability of the ship is fundamentally different.

Effects of the Coating Mixture on the Penetration of Liquids into Paper

The pigment coating of paper is usually performed to enhance the physical properties of paper and its printability. The coating generally makes paper whiter, brighter and more opaque. The properties of the coated paper depend, among others, on the porous structure of the coating developed, which is determined by the pigments, binders and their reactions. The influence of the type and quantity of coating components and ink absorption into the coating layer was studied in this work. Printing ink penetration was measured using a Penetration Dynamic Analyser with an HVL module (High Viscous Liquid). The evenness of liquid penetration into paper was measured using a Penetration Dynamic Analyser with a PEA module (Print Evenness Analyser). Results obtained indicate that all three variables – coating pigment type, latex dose and ink type – may have an equally strong influence on liquid and ink penetration,and thus on print quality.

Air-Core–Liquid-Ring (ACLR) Atomization Part II: Influence of Process Parameters on the Stability of Internal Liquid Film Thickness and Resulting Spray Droplet Sizes

Air-core–liquid-ring (ACLR) atomization presents a specific type of internal mixing pneumatic atomization. It can be used for disintegration of high viscous feed liquids into small droplets at relatively low gas consumptions. However, the specific principle of ACLR atomization is still under research and no guidelines for process and atomizer design are available. Regarding literature on pre-filming atomizers, it can be hypothesized for ACLR atomization that the liquid film thickness inside the exit orifice of the atomizer, as well as the resulting spray droplet sizes decrease with increasing air-to-liquid ratio (ALR) and decreasing feed viscosity. In this study, the time dependent liquid film thickness inside the exit orifice of the atomizer was predicted by means of computational fluid dynamics (CFD) analysis. Results were compared to high speed video images and correlated to measured spray droplet sizes. In conclusion, the hypothesis could be validated by simulation and experimental data, however, at high viscosity and low ALR, periodic gas core breakups were detected in optical measurements. These breakups could not be predicted in CFD simulations, as the simplification of an incompressible gas phase was applied in order to reduce computational costs and time. Nevertheless, the presented methods show good potential for improvement of atomizer geometry and process design as well as for further investigation of the ACLR atomization principle.

Upward interfacial friction factor in gas and high-viscosity liquid flows in vertical pipes

In this study, experiments were carried out in a vertical 60-mm internal diameter pipe with air and oil (viscosities 100–330 mPa s) constituting the gas and liquid phases. Superficial air and oil velocity ranges used were 9.81–59.06 m/s and 0.024–0.165 m/s, respectively. Visual observations and change in slope of pressure drop– plot were used to identify flow pattern transition to annular flow. Using the experimental data as well as other reported data, a new correlation to predict interfacial friction factor in upward gas–viscous liquid annular flow regime was developed. Compared to the performance of 16 existing correlations using higher viscosity liquids, that of the new correlation was better. The performance of another correlation we derived for predictions at both low and higher low viscous showed good agreement with measurements. In addition, a neural network model to predict the interfacial friction factor involving both low and high viscous liquids was developed and it excellently described the experimental data.

Interaction of two in-line bubbles of equal size rising in viscous liquid

Abstract The interaction of bubbles is the key to understand gas–liquid bubbling flow. Two-dimensional axis-symmetry computational fluid dynamics simulations on the interactive bubbles were performed with VOF method, which was validated by experimental work. It is testified that several different bubble interactive behaviors could be acquired under different conditions. Firstly, for large bubbles (d: 4, 6, 8, 10 mm), the trailing bubble rising velocity and aspect ratio have negative correlations with liquid viscosity and surface tension. The influences of viscosity and surface tension on leading bubble are negligible. Secondly, for smaller bubbles (d: 1, 2 mm), the results are complicated. The two bubbles tend to move together due to the attractive force by the wake and the potential repulsive force. Especially for high viscous or high surface tension liquid, the bubble pairs undergo several times acceleration and deceleration. In addition, bubble deformation plays an important role during bubble interaction which cannot be neglected.

Responsivity and sensitivity of piezoelectric MEMS resonators at higher order modes in liquids

Micromachined resonators completely submerged in liquids suffer from high viscous damping and low measurement signals compared to the operation in gaseous environment or in vacuum, which drastically decreases the sensing performance. A promising approach to decrease damping is the utilization of higher order modes. However, with the increase in mode order also the fluid-structure interaction decreases. In this context, it is unclear how the use of higher order modes helps, when targeting the characterization of fluid properties such as density and viscosity. In this paper, we demonstrate how the use of higher order modes affects both the responsivity and sensitivity of resonantly excited MEMS sensors when operated in liquids. The latter two key device parameters are experimentally investigated with respect to the inverse viscosity-density product (ρfluid·μfluid)-0.5 for the quality factor Q, the electrical conductance peak height ΔG and for the resonance frequency fres in standardized liquids with dynamic viscosity values ranging from 5 to 700 mPa∙s. It is observed, that an increase in mode order significantly increases the quality factor by a factor of 7, when comparing 1st to 10th order mode in a sample fluid with a dynamic viscosity of 5 mPa∙s), allowing the characterization of high viscous liquid with a dynamic viscosity up to 700 mPa∙s. Even so, no influence on the relative responsivity of Q and ΔG is observed. In fact, a decrease in the relative responsivity of fres is observed, so that no gain in response is achieved for all three parameters when the mode order is increased. However, higher order modes show significantly improved strain profiles on the surface of the resonating structure, resulting in increased ΔG values for the piezoelectric readout mechanism. Therefore, the sensitivity is substantially increased resulting in an improvement by a factor of ˜30, when comparing the 1st and 10th order mode. Even higher factors of ˜50 are obtained for Q and ΔG, what enables a minimal detectable (ρ·μ)−0.5 value of 0.000998 (mPa·s·kg/l)−0.5in a high viscous sample fluid with (ρ·μ)−0.5 = 0.040 (mPa·s·kg/l)−0.5 (for comparison: a common engine oil such as SAE 5W-40 has (ρ·μ)−0.5 = 0.039 (mPa·s·kg/l)−0.5at 0 °C).

Evaluation of Hydraulic Fracturing and Overcoring Methods to Determine and Compare the In Situ Stress Parameters in Porous Rock Mass

There are various methods to determine in situ stress parameters, but each method is having its own advantages and limitations. Among the methods available, the hydraulic fracturing method is the most commonly adopted procedure for in situ stress measurements because of its simplicity, reliability and economic viability. But, the limitations with this technique are that some assumptions implicit for this method such as that the rock mass is continuous and elastic. Moreover, the reliability and validity of this method becomes questionable in porous rocks that may encounter in underground tunnels. These limitations are experienced ever since the introduction of this method, especially in porous rocks. In general, the recognition of fracture initiation in the hydraulic fracturing test has not proved difficult. The relatively slow rates of pressurisation have ensured that when fracture initiation occurs, the sudden increase in volume has led to a marked drop in pressure in the porous section, which is easily recognised from the pressure record (Sjoberg et al. in Int J Rock Mech 40:999–1010, 2003). But the drop-in pressure in a porous rock is far more difficult to recognise. This is since pressure cannot be developed if the rate of leakage in the formation is equal to or higher than the flow rate applied for fracture initiation. This problem of non-generation of water pressure can be tackled by use of a high viscosity fluid. Stress measurement were conducted by hydraulic fracturing method by using high viscous liquid in porous rocks. The stresses evaluated by this technique were correlated with stress measured by overcoring method. The stress measured by overcoring method was used as bench-mark as this method does not suffer from the presence of porosity of the rock. This new technique will be helpful in conducting the stress measurements in porous rocks, which will be highly beneficial to both mining and hydropower related excavation.

Studies on synthesis of environment-friendly products for paint and coating applications

ABSTRACTIn the study, environment-friendly products, such as ketonic resins were prepared by self-polymerisation of ketonic monomers in the presence of a base catalyst using a high-pressure batch reactor. The cross-polymerisation reactions of ketonic monomers were also examined in the work. The effects of reaction parameters, such as reaction time, temperature, catalyst concentration and monomer concentration on physico-chemical properties of the product, such as physical state, hydroxyl value, iodine value, acid value, viscosity, average molecular weight, solubility, softening temperature and thermal stability have been studied. From the results, it was observed that the polymerisation reactions with methylcyclohexanone (MCH) or cyclopentanone (CP) monomers offered high viscous liquid resins. However, addition of small proportion (5–10 wt%) of MCH or CP along with cyclohexanone (CH) can play a significant role in obtaining a better quality product. It was also observed that CH and MCH monomers offered white colour resins, whereas CP monomer offered brown colour resins. The in-house-developed resins are thermally stable up to a temperature of around 180°C. From the overall investigation, it can be concluded that the in-house-developed ketonic resin products can be a suitable substitute of alkyd, ketone−aldehyde or phenol−aldehyde resins for paint and coating applications.

Experimental investigation on liquefaction of plastic waste to oil in supercritical water

In order to solve the problem of low thermal conductivity and high viscous molten liquid reaction product in the process of plastic liquefaction, the experiments of high impact polystyrene (HIPS) plastic liquefaction were carried out in supercritical water. In this paper, the effects of different operating conditions (temperature, time, feedstock concentration and pressure) on liquid products were studied. It is found that the novel phenomenon that the liquid products of HIPS plastic were mainly toluene and ethylbenzene rather than styrene, which was a product of polystyrene. The experimental results showed that plastic first depolymerized to form styrene and 1,3-diphenylpropane, which were then converted to toluene and ethylbenzene. The increase in temperature promoted this transformation process and some traces of polycyclic aromatic hydrocarbons also produced. At 490 °C, the maximum carbon liquefaction rate of 77.0 wt% was obtained, which was 6 times higher than the conventional pyrolysis, and the content of toluene and ethylbenzene were 14 wt% and 51.3 wt%, respectively. Increasing the reaction pressure and prolonging the reaction time all promoted the progress of the plastic liquefaction reaction, while increasing the feedstock concentration caused the carbon liquefaction rate to increase first and then slightly decrease.

Power Loss Mechanism and Flow Structure in Two-phase Flow Driven by a Rotating Disk

To clarify the mechanism of increase in the power loss for gas-liquid two-phase flow driven by a rotating disk in the cylindrical container, we investigated the influence of kinematic viscosity on torque acting on the surface of the rotating disk. For high viscous liquids, the torque on the disk in the two-phase flow is smaller than that in the single phase which is full of liquid, while for low viscous liquids, the torque in the two-phase flow is larger. We measured the spatial distribution of turbulent intensity via 2D-PIV, and visualized the vortical structure appearing near the free surface and the static casing in the two-phase flow condition via stereo-PTV. We discusse the effect of modifications in flow field on the torque changes in the two-phase flow condition.

Air-Core-Liquid-Ring (ACLR) Atomization: Influences of Gas Pressure and Atomizer Scale Up on Atomization Efficiency

Air-core-liquid-ring (ACLR) atomizers present a specific type of internal mixing pneumatic atomizers, which can be used for efficient atomization of high viscous liquids. Generally, atomization efficiency is considered as a correlation between energy input and resulting droplet size. In pneumatic atomization, air-to-liquid ratio by mass (ALR) is commonly used as reference parameter of energy input. However, the pressure energy of the atomization gas is not considered in the calculation of ALR. In internal mixing ACLR atomizers, it can be assumed that this energy contributes to liquid disintegration by expansion of the gas core after exiting the atomizer. This leads to the hypothesis that droplet sizes decrease with increasing gas pressure at constant ALR. Therefore, the use of volumetric energy density (EV) as a reference parameter of energy input was investigated at different gas pressures between 0.4 and 0.8 MPa. Furthermore, scale up-related influences on the atomization efficiency of ACLR atomization were investigated by use of an atomizer with enlarged exit orifice diameter. We can conclude that EV can be applied as a reference parameter of ACLR atomization processes with different gas pressures. However, within the range investigated no clear influence of gas pressure on atomization efficiency was found. Up-scaling of ACLR atomizers allows production of similar droplet sizes, but atomization efficiency decreases with increasing exit orifice diameter.

Numerical Analysis on Piezoelectrically Driven Jet Dispensing Mechanism for Nanoliter Droplet of High Viscosity Liquid.

Various research on a dispenser head applied with the technology of piezoelectric ceramics which has high response, force generation and resolution have been actively conducted. A piezoelectric dispenser head for functional high viscous liquid generates micro droplets utilizing a different mechanism with conventional valves. This mechanism makes it difficult to calculate the pressure build-up and flow quantity. Because of this difficulty, proper displacement of a tappet cannot be selected and the displacement of the piezoelectric ceramic is being used with excessive amplification. To address these issues, a piezo dispenser head has been modeled to numerically analyze this mechanism. The mechanism has been simulated to calculate the pressure build-up and flow quantity. In addition, the load on the tappet was calculated, and the appropriate displacement of the tappet was confirmed. In this study, we have succeeded in numerically analyzing the mechanism of the piezoelectric dispenser head and we confirmed that the displacement of the appropriate tappet is about 200 μm; at this time the load on the tappet is about 3.7 N and the droplet volume is about 19.89 nL.

On the Spraying Modality of Liquids by Pyroelectrohydrodynamics

We present for the first time an investigation on the spraying modality for the pyroelectrohydrodynamic (pyro-EHD) system. We show that the pyro-EHD spray (p-Spray) works well in the range from far field (d > 10 mm) to near field (d < 2 mm) without the need of external voltage and without the needs to change the experimental apparatus in that wide range of distances. Because the proposed method works without a counter electrode, no limitations are connected with the geometric shape of the substrate on which the spray coating is deposited. We report on several examples of the formation of disperse sprayed droplets, whose size can be varied between hundreds of micrometers and hundreds of nanometers, as well as on the production of sprayed pattern footpaths. The results reported here demonstrate the direct writing of spray patterns of nano/microdroplets with different materials in a very wide range, that is, from low- to high-viscous liquid solutions. Finally, as an example of application, we show the use of the p-Spray for the fabrication of silver-coated devices showing antimicrobial properties of the pattern produced by the p-Spray through a customizable and environmental friendly approach.