Diameter Glass Beads Research Articles

Experimental Studies on Hydrodynamics Characteristics of Co-current Three Phase Fluidization Using Different Sizes of Glass Beads and its Prediction by Fuzzy Logic

The experiment was carried out with different sizes of Glass beads. That is Glass beads of diameter 0.2 cm, 0.4 cm, 0.6 cm. Water was used as a continuous phase and air was used as a dispersed phase. These three different sized Glass beads were used as solids for co-current studies. The three sections of the experimental setup viz. gas liquid disengagement section, test section and gas liquid distributed section. The experiment was conducted with Glass beads with varying liquid velocities and keeping constant gas velocity 0.16985138 cm/sec, 0.212314225 cm/sec, 0.304317056 cm/sec, 0.346779901 cm/sec. The graphs were plotted and their effects on individual phase holdups for various particle sizes were studied. Pressure drop of fluids in the fluidized bed was measured by using mercury manometer and by using ethyl acetate manometer. The phase holdups like solid, liquid, gas were determined, liquid holdup and solid holdup decreases with increase in liquid velocity whereas gas holdup increases with increases in liquid velocity. With the experimental data, simulation studies were carried out using Fuzzy Logic.

Study on the Reflecting Properties of PET Composites with TiO<sub>2</sub>, Glass Beads and Fluorescent Brightener

Subscript textIn this paper the influence of glass beads (GB), Fluorescent Brightener (FB), titanium dioxide (TiO2) on light reflecting performance of PET was studied. The composites of PET, GB, FB, and TiO2 were prepared by twin screw extruder. The dispersive characterization of GB with diameter of 20μm to 90μm was observed by the optical microscope and the reflective properties of injected sample of PET composites were evaluated by experiment. The results show that GB are dispersed homogeneously in PET matrix and the reflectivity of the PET/GB samples increase with the decrease of the diameter of GB. Introduction of FB in PET/GB composites leads to the increase of the reflective light within wavelength from 400 to 600nm, increasing by 10%. By adding TiO2 into PET, the reflectivity of PET composites could be increased over 80%. And by adding FB into PET/TiO2 composites, the reflectivity of PET/TiO2/FB within wavelength from 400 to 600nm could be increased up to 110% , due to fluorescent brightening.

Steam chamber evolution during SAGD and ES-SAGD in thin layer oil sand reservoirs using a 2-D scaled model

Bitumen recovery from thin oil sand reservoirs was modeled on a 150:1 scale, two-dimensional apparatus based on the theory of steam assisted gravity drainage. Injections of only steam and of steam and organic solvent were compared at high temperature (180°C) and high pressure (686–882kPa). Oil sand was simulated using homogeneously mixed extra heavy oil (<10mPas at 200°C) and glass beads (diameter 1.5mm) to achieve a porosity of 0.3. Steam temperatures, pressures, flow rates, and the evolution of steam chambers were monitored during the extractions. Recovery factor and steam chamber growth rate were compared. Extraction using steam with 3.0–7.4vol% hexane improved the bitumen recovery factor by at least 30%. The added solvent resulted in the steam chamber reaching its greatest area 1200s sooner than when using steam alone, equivalent to 0.9 year in the field. The extra heavy oil was analyzed by HPLC before and after extraction and the relative compositions of SARA were compared. The oil's asphaltene content was reduced from 17.6wt% to 10.8wt% and to 9.7wt% by extraction without and with the added solvent, respectively. Amounts of aromatics and resin were increased by both extraction methods.

Hydrodynamic Characteristic of Large Particles in Vibrated Fluidization Bed

Hydrodynamic for 2D vibrated fluidized bed was studied with large particle glass beads of average diameters are less than 1.5mm.The effect of the vibration strength, the static bed height and the particle diameter on the critical fluidization velocity was analyzed. The results show that the critical fluidization velocity decreases with the increase of the vibration strength, and increases with increases of the static bed height and particle diameter. The effect of vibration on critical fluidization velocity was more significant than decrease the bed height and particle diameter. The empirical correlation equations to predict the critical fluidization velocity was established, and the results of the prediction were compared with the experimental data, the error is in range of ±10%. The results can provide important meaning on theory and instructing practice for developing the new drying technology with high drying efficiency and low dissipation of energy.

Flow regime transition identification in three phase co‐current bubble columns

AbstractBubble columns have wide applications in absorption, bio‐reactions, catalytic slurry reactions, coal liquefaction; and are simple to operate, have less operating costs; provide good heat and mass transfer. Experiments have been performed for identifying transition regime in a 15 cm diameter bubble column with liquid phase as water and air as the gas phase. Glass beads of mean diameter 35 µm have been used as solid phase. The superficial gas velocity is in the range 0 ≤ Ug ≤ 16.3 cm/s and superficial liquid velocity in the range of 0 ≤ Ul ≤ 12.26 cm/s. Solid loading up to 9% (w/v) has been used. Pressure signals have been measured using differential pressure transducers (DPTs) at four different axial locations. Classical analysis (Wallis approach and Zuber–Findlay approach), Statistical analysis and Fractal analysis have been used for regime transition identification. Statistical analysis and Fractal analysis have shown almost the same transition points for all the liquid and gas velocities. Effect of solid concentration, liquid velocity and gas velocity over transition regime has also been studied. As the solid concentration is increased it has insignificant effect over transition regime for lower values (&lt;1%), while transition values decrease for higher solid concentration (&gt;1%). © 2012 Canadian Society for Chemical Engineering

Undersized (12.5 mm diameter) glass beads with minimal amount (11 mg) of geochemical and archeological silicic samples for X‐ray fluorescence determination of major oxides

The small glass bead technique was developed to assay precious silicic samples for geochemical and archeological analyses. Undersized (12.5 mm diameter) glass beads were prepared for wavelength dispersive X‐ray fluorescence determination of major oxides (Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, MnO, and total Fe2O3). Synthetic calibration standards were prepared by compounding chemical reagents (oxides, carbonates, and diphosphate). For reliable calibration, recipe compositions of standard specimens were constructed on the basis of the evenness of plot intervals on a calibration curve. Calibration curves showed good linearity (correlation coefficient: r &gt; 0.998). Analytical results of major oxides in granitic and basaltic rocks, obsidian, and ancient pottery were obtained with good precision (relative standard deviations were the following: &lt;3% for more than 10.0 mass% of analyte, &lt;5% for 1.0–10.0 mass% of analyte, and &lt;15% for 0.1–1.0 mass% of analyte). Lower limits of detection were roughly a sub‐percentage of analyte in an unprepared sample: 0.3 mass% for Na2O, 1.0 mass% for SiO2, 0.01 mass% for MnO, and so on. The present preparation reduced the following analytical scales: (1) amount of sample from 400 mg to 11 mg (97% cutting out), (2) amount of Li2B4O7 as an alkali flux from 4000 mg to 396 mg (90% cutting out), and (3) weight of platinum crucible from 80 g to 12.5 g (84% cutting out). This small‐scale preparation might enable us to conduct destructive pretreatment of valuable and limited silicic samples such as archeological ceramics and stone tools, geochemical minerals in rock, and sediments and sand. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Collision of a vortex ring on granular material. Part II. Erosion of the granular layer

In our previous paper (part I), an experimental result was presented on the normal impact of a vortex ring on the granular layer (glass beads of diameter 0.10 mm), which was placed at a specified distance from the outlet of the vortex ring generator. The Reynolds number of the vortex ring ranged from 1000 to 6000, whereas the traveling distance ranged from 2 to 13 times of the diameter of the vortex ring generator nozzle. In part I, the deformation of the vortex ring impacting on the granular layer and the development of the secondary vortex ring were focused. In this paper (part II), the erosion of the granular surface by the vortex ring is described. Various patterns were found depending on the Reynolds number of the vortex ring and the traveling distance. Two patterns, one (grooves) which has radial striations from the central depressed region to the outer edge of the rim and the other (dimples) which is characterized by isolated small depressions around the outer edge of the rim, are examined in detail. The formation processes of these patterns are elucidated in terms of the deformation of the vortex ring.

Collision of a vortex ring on granular material. Part I. Interaction of the vortex ring with the granular layer

An experimental study was carried out on the normal impact of the vortex ring on the granular layer. The Reynolds number of the vortex ring ranged from 1000 to 6000, whereas the distance to the granular layer (glass beads of diameter 0.10 mm) varied between 2 and 13 times of the diameter of the vortex ring generator nozzle. The velocity field was visualized by the sodium fluorescein and was measured by particle image velocimetry or particle tracking velocimetry. The flow field in the vicinity of the granular surface was also visualized by an almost mono-layer of fine particles deposited on the main granular layer, which elucidated the development of the secondary and tertiary vortex rings. Generally speaking, the characteristics of the granular layer are found to be similar to a liquid plane for the impact of a vortex ring of a smaller impulse, whereas it is closer to a solid plane for a vortex ring of a larger impulse. For the vortex ring with a much larger impulse, the granular layer is engraved, whose patterns reflect the deformation of the primary and/or secondary vortex ring due to the interaction with the granular layer (as will be described in part II).

Gas Hold-up in Three Phase Co-current Bubble Columns

Abstract Bubble columns are used in a large number of applications in chemical engineering. The important variables that affect the gas holdup, bubble dynamics and flow regime in a bubble column are gas and liquid velocities, liquid viscosity, liquid surface tension, design of the gas distributor, solid concentration and column diameter. Experiments have been performed in a 15 cm diameter co-current slurry bubble column with liquid phase as water and air as the gas phase. Glass beads of mean diameter 35 μm have been used as solid phase. Solid loading up to 9% has been used. The superficial gas velocity varies from 1.0 to 16.28 cm / s and superficial liquid velocity varies from 0 to 12.26 cm / s. Effects of liquid height, liquid velocity, gas velocity and solid concentration over gas holdup for both two and three phase co-current flows have been studied. For batch case the liquid height didn’t affect the gas holdup. The gas holdup increases with increase in gas velocity for both two and three phase co-current columns. For two phase and three phase flow up to 1% solid loading; at low superficial gas velocity i.e. in the homogeneous regime, the increase in liquid velocity doesn’t show any change in the gas holdup. For higher gas velocities i.e. in the heterogeneous regime, increase in liquid velocity decreases the gas holdup rapidly. Above 1% solid loading, liquid velocity effect over gas hold-up is negligible. With increase in solid concentration for co-current bubble column the gas holdup slightly increases or remains constant up to 5% loading; beyond this loading there is a significant decrease in gas holdup

I131 多孔質の不均質性がガス浸透及びトラップに与える影響(OS-16: 多孔質体内の熱物質輸送と応用(3))

In present study, we investigate effect of heterogeneity of porous medium on gas saturation after drainage and imbibitions processes. The heterogeneity is modeled with the packed beds layered with different glass beads of grain diameter. The packed beds have two types of heterogeneity in serial and parallel directions with respect to the mean flow. Initial gas saturation is strongly affected by capillary entrance pressure at the interface of heterogeneous porous structures.

Micromanipulation using cavitational microstreaming generated by acoustically oscillating twin bubbles

This paper describes a novel non-invasive micromanipulation technique that employs the cavitational microstreaming generated by acoustically oscillating twin bubbles. First, a single acoustically oscillating bubble was attached to the tip of a rod that was combined with a three-dimensional traverse system, and a fish egg (diameter: 1mm) was then manipulated in an aqueous medium. Although the microstreaming generated by the single oscillating bubble was sufficiently strong to push and move the fish egg, the manipulation direction was uncontrollable. Hence, to improve the manipulation controllability, identical twin bubbles with the same size and resonant frequency were employed. The identical gas bubbles were generated on a microfabricated chip comprising sharp tip-shaped electrodes by employing an electrochemical method, electrolysis, and controlling the applied voltage and time. Subsequently, the bubbles were sequentially transferred to the tips of a U-shaped rod coated with a hydrophobic layer to improve the surface adhesion. The force generated from the acoustically oscillating bubbles and its direction were analyzed under various acoustic excitation conditions by using high-speed images. Our results showed that the generated force was proportional to the bubble oscillation amplitude, whereas the direction of the force depended on the distance between a bubble and object. A steel ball (500μm diameter) was used for investigating the force direction. When a bubble (600μm diameter) was acoustically excited, the steel ball was pulled toward the oscillating bubble when the distance between the bubble and ball was short (<3mm), whereas the steel ball was pushed away from the oscillating bubble when the distance was long (>3mm). Finally, a fish egg (diameter: 1mm) and glass beads (diameter: 100μm) were experimentally manipulated using acoustically oscillating twin bubbles.

An Empirical Correlation for Maximum Penetration Depth of a Particle Impacting on a Free Surface at its Critical Velocity Condition

Film flotation is a process which consumes much lower energy than mechanical cells. The extended film flotation technique is to separate mineral mixtures by different critical impact velocities. In this study the maximum penetration depth of a particle at its critical condition was investigated experimentally and theoretically. Experiments were performed using spherical glass beads of different diameters and hydrophobicities and different liquids. The penetration depth at critical condition was recorded and measured using high speed video camera. Buckingham’s PI theorem was applied to analyse the dimensionless groups, and then an empirical correlation for penetration depth was obtained by partial least squares method. It was found that the prediction results of the empirical equation were in good agreement with the measurements. Also, the influence factors were analysed. It was noticed that the hydrophobicities of particle and particle-liquid density ratio had most significant effects on the penetration depth.

Detachment of coarse particles from oscillating bubbles—The effect of particle contact angle, shape and medium viscosity

This paper examines the detachment of coarse particles from oscillating bubbles as a function of particle hydrophobicity and shape, as well as medium viscosity. The detachment experiments were conducted using a novel electro-acoustic technique for both ground quartz particles and spherical glass beads of various diameters and hydrophobicity. The detachment force for both types of particles, calculated from the maximum vibration amplitude at which a particle detaches from a bubble, increased with an increase in the contact angle of particles and viscosity of the suspending medium. At low vibration frequencies, the quasi-static model predicts the experimental detachment force reasonably well. In contrast, at high vibration frequency and, particularly, in high viscosity medium, the quasi-static model does not predict the experimental detachment force. It is hypothesised that the magnitude of the detachment force is determined by the dynamic contact angle, which is governed by the velocity of movement of the three phase contact line. Larger detachment forces were observed for the quartz particles compared to that of the spherical glass beads of the same size range and similar contact angle value. The stability of the bubble-particle aggregates at high viscosity has been related to the dynamic contact angle of particles. At high viscosity, the rate of movement of the three phase contact line, which governs the dynamic contact angle, is reduced thus resulting in more stable bubble-particle aggregates.

Nanoparticle Flotation Collectors: Mechanisms Behind a New Technology

This is the first report describing a new technology where hydrophobic nanoparticles adsorb onto much larger, hydrophilic mineral particle surfaces to facilitate attachment to air bubbles in flotation. The adsorption of 46 nm cationic polystyrene nanoparticles onto 43 μm diameter glass beads, a mineral model, facilitates virtually complete removal of the beads by flotation. As little as 5% coverage of the bead surfaces with nanoparticles promotes high flotation efficiencies. The maximum force required to pull a glass bead from an air bubble interface into the aqueous phase was measured by micromechanics. The pull-off force was 1.9 μN for glass beads coated with nanoparticles, compared to 0.0086 μN for clean beads. The pull-off forces were modeled using Scheludko's classical expression. We propose that the bubble/bead contact area may not be dry (completely dewetted). Instead, for hydrophobic nanoparticles sitting on a hydrophilic surface, it is possible that only the nanoparticles penetrate the air/water interface to form a three-phase contact line. We present a new model for pull-off forces for such a wet contact patch between the bead and the air bubble. Contact angle measurements of both nanoparticle coated glass and smooth films from dissolved nanoparticles were performed to support the modeling.

Capillary Induced Small-Strain Stiffness for Hydrophilic and Hydrophobic Granular Materials: Experimental and Numerical Studies

ABSTRACT The negative pore-water pressure in unsaturated soils increases the inter-particle force and small-strain stiffness, though this concept is only valid in wettable soils. The non-wetting nature of soils originating from the organic contamination of geoenvironments and natural hazards causes unexpected geo-events such as impermeation of water and hillslope runoff due to the changes in soil wettability. This study presents an experimental and numerical investigation to understand the evolution of capillary force and pressure for unsaturated soils whose surface wettability is wettable (hydrophilic) and water-repellent (hydrophobic). Hydrophobic granular materials are synthesized by the silanization technique with 0.5 mm diameter glass beads. The small-strain shear stiffness and corresponding degree of saturation are continuously monitored during evaporation for both specimens. The peak value of maximum shear stiffness is captured at a degree of saturation S~5.5% for hydrophilic specimen, while the hydrophobic specimen shows a quasi-constant small-strain stiffness during evaporation. The minimization of free energy for the liquid bridge between the two-particle system allows the attractive and repulsive capillary force and pressure produced between particles to be numerically estimated. The regime of zero-capillary pressure is identified depending on the contact angle and volume of liquid bridge. The measurement of small-strain stiffness combined with the numerical simulation of both hydrophilic and hydrophobic specimens clarifies the governing factors to determine capillarity in the granular materials and provides insight into the phenomenological observation of capillary pressure for unsaturated soils.

Absolute backscatter coefficient estimates of tissue-mimicking phantoms in the 5–50 MHz frequency range

Absolute backscatter coefficients in tissue-mimicking phantoms were experimentally determined in the 5-50 MHz frequency range using a broadband technique. A focused broadband transducer from a commercial research system, the VisualSonics Vevo 770, was used with two tissue-mimicking phantoms. The phantoms differed regarding the thin layers covering their surfaces to prevent desiccation and regarding glass bead concentrations and diameter distributions. Ultrasound scanning of these phantoms was performed through the thin layer. To avoid signal saturation, the power spectra obtained from the backscattered radio frequency signals were calibrated by using the signal from a liquid planar reflector, a water-brominated hydrocarbon interface with acoustic impedance close to that of water. Experimental values of absolute backscatter coefficients were compared with those predicted by the Faran scattering model over the frequency range 5-50 MHz. The mean percent difference and standard deviation was 54% ± 45% for the phantom with a mean glass bead diameter of 5.40 μm and was 47% ± 28% for the phantom with 5.16 μm mean diameter beads.

Heat Transfer Between Gas-Solid Phases Within Packed Particle Beds

A new method is presented to determine the internal heat convection coefficients for air flowing steadily through a bed of spherical particles. In this technique, a series of step change experiments are carried out on beds of glass beads of different diameters that are subjected to a temperature step change in the inlet airflow at different flow rates. Thermocouples are arranged along the particle bed height to record the particle temperature distribution and inlet/outlet air temperatures at any time. A theoretical energy analysis of particle beds to determine the convective heat transfer coefficients is performed for the short time duration when the experimental data show that temperature distribution along the airflow direction at any time is almost spatially linear and the temperature at any specific position is almost temporally linear. The energy change of the particle beds within this time duration is shown to be a function of the heat convection coefficient. Therefore, a new correlation, in terms of Nusselt number versus Reynolds number (, with uncertainty limits at 95% confidence level, is developed and found to be in good agreement with most other correlations developed by other researchers for beds of similar spherical particles.

Effect of a dispersed immiscible liquid phase on the hydrodynamics of a bubble column and ebullated bed

Secondary undesired reactions in ebullated bed resid hydroprocessors can generate an additional dispersed liquid phase, referred as mesophase, which is denser and more viscous than the continuous liquid phase and affects the operation and transport phenomena of the fluidized bed. This study investigates the effect of a dispersed immiscible liquid phase on the overall phase holdups, bubble properties, and fluidization behavior in a bubble column and ebullated bed. The experimental system consisted of biodiesel as the continuous liquid phase, glycerol as the dispersed liquid phase, 1.3 mm diameter glass beads, and nitrogen. The addition of dispersed glycerol reduced the gas holdups in the bubble column for the studied gas and liquid superficial velocities. Dynamic gas disengagement profiles reveal a rise in the large bubble population and reductions to the small and micro bubble holdups when increasing the glycerol concentration. Liquid–liquid–solid bed expansions at various liquid flowrates confirm particle agglomeration in the presence of a more viscous dispersed liquid phase. Overall phase holdups in a gas–liquid–liquid–solid ebullated bed were obtained while varying the gas and liquid flowrates as well as the glycerol concentration. A coalesced bubble flow regime was observed in the bed region without glycerol whereas the addition of glycerol resulted in the dispersed bubble flow regime due to particle clustering and a greater apparent particle size. The resulting bubble flow regime increased the bed and freeboard region gas holdups due to enhanced bubble break-up. Observations of the fluidized bed behavior following the addition of the dispersed glycerol are also discussed.

H114 多孔質内において毛管力でトラップされた超臨界CO_2気泡のポアスケール可視化(OS11 温暖化対策とCO_2削減技術)

Carbon dioxide capture and storage in geological formations (CCS) is recognized as a promising method for decoupling fossil fuel use carbon emissions. We focused on capillary trapping, because capillary trapping is considered a high long-term stability. Trapped bubbles in packed beds of glass beads have been visualized by means of X-ray CT at pore scale for supercritical CO_2 at reservoir condition (pressure: 8.5MPa, temperature: 45℃) and for nitrogen at laboratory room condition. When the diameter of glass beads is same, distribution of volume of trapped bubbles is similar for each condition. The morphology of the interface between the supercritical CO_2 and water suggests that CO_2 is non-wetting to glass beads. Residual gas saturation increases with a decrease in the diameter of glass beads. Residual gas saturation can be expressed as a function of the reverse Bond number for each condition. With decrease in glass beads diameter, residual gas saturation increases, and trapped bubble volume is shifts to be large compared with glass beads volume.

216205 充填層内における液体CO_2の流動挙動に及ぼすハイドレートの影響(一般05 流体力学・流体工学3)

The purpose of the present study is to investigate the influence of CO_2 hydrate on the flow of liquid CO_2 injected in a packed bed that simulated seabed with glass beads. In order to reveal the influence of CO_2 hydrate, differential pressure and temperature are measured under both condition of CO_2 hydrate generation and no-generation. As the result, Temperature difference decreased with increase of flow rate in the condition of any diameter of glass beads. And, friction factor is compared with the Ergun's equation which is proposed for single-phase flow in a porous media. As the result, both condition of CO_2 hydrate generation and not, the measured friction factor is larger than that estimated with Ergun's equation. And, in the middle part, there are no difference of the friction factor between the hydrate generation and no-generation condition.