Different Sizes Of 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.

Darcy’s law for yield stress fluid flowing through a porous medium

We measured the pressure drop vs flow rate during the flow, in a wide range of velocities, of well controlled yield stress fluids through confined packings of glass beads of different sizes. A detailed analysis of the data makes it possible to extract a general expression for the pressure drop vs flow rate curve through a porous medium as a function of the flow rate and the characteristics of the system. This general law has a form similar to the Herschel–Bulkley model describing the rheological behavior of such fluids in simple shear, i.e. it expresses as the sum of a critical (yielding) pressure drop and a flow rate dependent term. This law involves the rheological parameters of the fluid, one characteristic length of the medium, and two coefficients which only depend on the structure of the porous medium. The first coefficient is related to the path of maximum width throughout the porous medium while the second coefficient reflects the pore size distribution. The values of these coefficients were determined in the case of a granular packing.

Characteristics of acoustic emissions induced by fluid front displacement in porous media

The dynamics of fluid displacement in porous media often affect phase entrapment and shape macroscopic transport properties and thus are of considerable interest for a range of natural and engineering applications. The macroscopic motion of a displacement front is composed of numerous abrupt pore‐scale invasion events that involve rapid interfacial jumps and reconfigurations with associated mechanical and interfacial energy release detectable as acoustic emissions (AE). We conducted systematic experiments of fluid displacement and measured associated AE during passage of fluid fronts (primarily drainage) within assemblies of glass beads of different sizes. Results indicated distinct acoustic signatures associated with different displacement processes, reflecting dependency on porous media pore size, displacement flow rate, and liquid properties. The rich AE signals associated with front dynamics exhibited power law relationships between the number of AE events and their amplitudes, reminiscent of avalanche‐like invasion processes. In addition to AE signals emanating from rapid emptying or filling of pores (Haines jumps), other processes such as redistribution and interfacial reconfigurations behind a drainage front and grain rearrangement may generate AE. Characteristic AE signatures generated by displacement processes in different media and under various boundary conditions offer a promise for remote detection of pore‐scale fluid interfacial dynamics in porous media that may shape macroscopic transport properties (e.g., linked with phase entrapment).

Production Characteristics of the Steam-Assisted Gravity Drainage (SAGD) and Solvent-Aided SAGD (SA-SAGD) Processes Using a 2-D Macroscale Physical Model

There are extensive bitumen deposits in Canada that, with the development of sustainable exploitation technologies, can satisfy the energy requirements of the nation for more than a century. The currently available surface mining and in situ recovery techniques are applicable to only ∼15% of the known in-place resources. There is an obvious need for improved technology to make more of the in-place resources exploitable. This paper is aimed at studying the macroscale performance of the steam-assisted gravity drainage (SAGD) and the solvent-aided SAGD (SA-SAGD) processes. A two-dimensional (2-D) physical model of porous media was designed and fabricated for the purpose of implementing these two processes. The physical model was packed with different sizes of glass beads to create porous media with different permeability values. Athabasca bitumen was used as the oil phase. All the SAGD and SA-SAGD experiments were performed in an isothermal jacket as the controlled-temperature environment to reduce the amount of undesired heat loss from the model to the surrounding environment. In addition, layers of insulating materials attached to wooden frames were used to cover the back and side faces of the packed model to further reduce the heat losses. All the experiments were conducted under the free uptake flow circulation methodology at atmospheric pressure. For the SAGD experiments, replicate trials were also designed and conducted in order to ensure the repeatability of the experiments. According to the SAGD experimental results, the average mobile oil production rate, as well as that of the dead oil, is constant over the course of the process. When all other experimental variables are unchanged except the porous medium permeability, the higher the permeability of the porous medium, the higher the amount of water content of the produced mobile oil, but the lower the steam-to-oil ratio. The residual oil saturation in the invaded region of the porous medium was obtained to be ∼3%–4.6% of the total pore volume at higher and lower permeability levels, respectively. Moreover, the microstructure of the dispersed water condensate droplets in the continuum of the produced mobile oil was studied with the aid of an advanced photomicrography system integrated with image processing unit. It was determined that water condensate droplets with equivalent sizes as small as 5 μm were dispersed in the mobile oil background. Average droplet size values were measured for both of the permeability levels used in the SAGD experiments, based on the image processing of the microscopic snapshots taken from the produced emulsion samples. One SA-SAGD trial was also conducted in order to demonstrate the enhancement made in the production performance of the SAGD process, following the coinjection of solvent with steam. It was determined that the average mobile oil and dead oil production rates of the SA-SAGD process are reasonably constant over the course of the experiment. In the SA-SAGD process, there were enhancements of ∼18% and 20% in the mobile oil and dead oil production rates, respectively, compared to the corresponding average values in the SAGD experiments at similar permeability values. The average water production rate and the SOR values of the SA-SAGD experiment were ∼9% and ∼35% less than those of the corresponding SAGD trials, respectively. The microscopic snapshots of the produced water in oil emulsion were also studied for the case of the SA-SAGD experiment and it was obtained that water condensate droplets with an equivalent size of as small as 5 μm were dispersed in the continuum of the produced mobile oil. In addition, an average water droplet size range was determined based on the measurements using image processing techniques.

High-Frequency Sound-Speed, Attenuation, and Reflection Measurements Using Water-Saturated Glass Beads of Different Sizes

Sound propagation in water-saturated glass beads was studied under controlled laboratory conditions over a frequency range from 200 to 900 kHz for sound-speed measurements and from 200 to 800 kHz for attenuation measurements. The influence of the grain size on both p-wave speed and attenuation was studied using three kinds of glass beads. A strong negative dispersion of the sound speed over the whole frequency range studied was observed with the three different populations of beads used in this experiment (mean grain size: 272 μm, 520 μm, and 1.33 mm). In addition, it was found that not only does the attenuation increase nonlinearly with frequency, but it also depends on the size of the beads. These results are consistent with earlier measurements performed by other researchers over the same frequency range with glass beads of about the same sizes. In this paper, we also discuss the results of the measurement (over a wide frequency range: 200 kHz-1.5 MHz) of the reflection coefficient of a thick slab of glass beads whose surface was smoothed, as well as the correlation between the behavior of this reflection coefficient and the negative dispersion of the sound speed. For this experiment, five populations of beads (91 μm, 272 μm, 520 μm, 133 mm, and 2.98 mm) were used.

Radial segregation of ternary granular mixtures in rotating cylinders

We carry out an experimental study of the equilibrium segregation of ternary granular mixtures in a rotating cylinder. In all the experiments, 50% of the volume of the cylinder is filled with the granular mixture and the rotational speed used ensures operation in the rolling regime of flow. Mixtures of spherical particles differing only in size and of spherical particles differing in size and density are considered, using steel balls and glass beads of different sizes. Volume fractions of the components (\({\phi}\)) are measured by sampling at different radial positions (r) to yield the radial volume fraction profiles (\({\phi(r)}\)). Results for mixtures differing only in size of the components indicate that the segregation process is nearly independent of the sizes of the large and middle size particles for the same size of small particles. In the case of mixtures with different size and density components, the segregation patterns depend on the direction of the resultant driving force. In many of the mixtures considered, the pattern of segregation can be qualitatively predicted by considering binary interactions between the components. However, in some mixtures, ternary interactions are found to determine the pattern obtained.

Acoustical characterization of rigid porous materials.

In an earlier study [K. M. Li, J. Acoust. Soc. Am. Soc. 123, 1352–1363 (2008)], an analytical expression has been derived to predict the penetration of sound into a rigid porous ground due to a monopole source. In the present study, this analytical formula has been exploited for a numerical method to characterize the acoustical properties of rigid porous materials. They can be obtained from a pair of excess attenuation spectra measured above and below a thick layer of the material. Specifically, its propagation constant and complex density ratio can be determined from the measured data by a downhill simplex method. A series of preliminary indoor measurements was conducted in an anechoic chamber for measuring the propagation of sound above and below a layer of glass beads of different sizes. Based on the measured excess attenuation spectra, the acoustical characteristics of two different sizes of glass beads were determined numerically. These acoustical parameters were compared with the predictions based on the classical impedance model.

Enhancement of dilution and transverse reactive mixing in porous media: Experiments and model-based interpretation

Transport and natural attenuation of contaminant plumes in groundwater are often controlled by transverse dispersion. The extent of mixing between dissolved reaction partners at the fringe of a plume determines its length and depends strongly on the groundwater flow field. Transient flow conditions as well as the focusing of the flow in high-permeability zones may enhance transverse mixing of dissolved species and, therefore, create favorable conditions for the natural attenuation of contaminant plumes. The aim of the present study is to experimentally test the influence of these processes on solute mixing and to directly compare the results with those under analogous homogeneous and steady-state conditions. We have performed conservative and reactive tracer experiments in a quasi two-dimensional tank filled with glass beads of different sizes. The experiments have been carried out in both homogeneous and heterogeneous porous media under steady-state and transient (i.e. oscillating) flow fields. We used fluorescein as conservative tracer; whereas an alkaline solution (NaOH) was injected into ambient acidic water (HCl) in the reactive experiments. A pH indicator was added to the reacting solutions in order to visualize the emerging plume. We simulated the laboratory experiments with a numerical model and compared the outcomes of the model with the measured concentrations at the outlet of the tank and with the observed tracer plumes. Spatial moments, a newly defined flux-related dilution index, the product mass fluxes and the reaction enhancement factors were calculated to quantify the differences in mixing and reaction extent under various experimental conditions. The results show that flow focusing in heterogeneous porous media significantly enhances transverse mixing and mixing-controlled reactions, whereas temporally changing flow fields appear to be of minor importance.

Studies on the determination of shear wave velocity in sands

Laboratory investigations such as resonant column, cyclic triaxial, and torsional shear tests are usually conducted on undisturbed and reconstituted sand samples in order to determine their shear modulus, which can be used to compute shear wave velocity. However, these methods are extremely cumbersome and indirect, they employ cost-intensive instrumentation, and they require trained manpower. These problems can be overcome by using bender elements, which yield the shear wave velocity of sands directly, easily, and quite rapidly. In this context, efforts made by earlier researchers in developing empirical relationships (based on bender elements and resonant column techniques) which can be employed to compute shear wave velocity in sands are worth consideration. Although these relationships take into account parameters like effective stress and void ratio, they do not directly incorporate fundamental characteristics of sands such as their state (i.e. dry or saturated) and the particle size. Thus a generalized relationship, which can be used to compute shear wave velocity in sands in either the dry or saturated state, has been developed. Experiments were conducted on samples of sand and glass beads of different sizes and the results were used to demonstrate the utility and efficiency of the relationship. Details of the methodology developed for this purpose are also presented in this paper.

Shear deformation of binary mixtures of dry particulate solids

Abstract The shear deformation behavior of dry granular materials is of interest in the analysis of flowability, mixing, segregation and degradation. Quite often the particulate systems are mixtures of materials with a wide size distribution. In spite of a large amount of work reported in the literature, the shear behavior of poly-disperse systems has not been widely addressed. In this paper experimental work using an annular shear cell and numerical simulations by the distinct element method (DEM) have been carried out to quantify the normal and shear stress behavior of assemblies made of binary mixtures. The experimental results on mixtures of different sizes of glass beads show a linear relationship between the normal and shear stresses with a slope which depends on the shear rate and particle size ratio. This is an indication of flow in the intermediate regime between the quasi-static and rapid shear flows. The results also indicate a highly non-linear particle displacement distribution across the shear layer. Numerical simulations using the DEM agree qualitatively well with the experimental results for the normal-shear stress behavior.

Preparation of controlled particulate mixtures with glass beads of different sizes

A method of mixing/preparing binary and ternary mixtures of glass beads was developed using a viscous solution of glycerol in water. After mixing, the mixture was transferred to a prismatic vessel and glycerol was washed out. The different sized beads were differently coloured and digital pictures taken from each face were automatically treated by image analysis to determine the coloured fraction present in each face. Statistical analysis showed that no significant deviation existed in the colour distribution of each of the four faces. A chi-square test showed that a uniform distribution could be accepted for the beads, no segregation of bead size nearby the edges was observed and that no wall effect was present. The two-dimensional picture obtained by image analysis was converted to the corresponding three-dimensional distribution, from which the expected bed porosity was inferred. The porosity previously estimated was compared with the experimental porosity determined by gravimetry directly on the bed. No significant deviations were found, thereby proving that the mixing method developed was reliable. Hundreds of experiments were done showing a very high reproducibility. The developed method was further used for studies on mixing of binary and ternary mixtures. In certain conditions (mixtures enriched with large size particles and having a significant difference in size) a segregation layering effect took place and the bottom layer presented a composition corresponding to the packing with the smallest porosity possible.

Glomalin production by an arbuscular mycorrhizal fungus: a mechanism of habitat modification?

We report on a novel mechanism by which arbuscular mycorrhizal fungi may be able to modify a sub-optimal growth environment to their advantage by secreting the glycoprotein glomalin, which is highly correlated with soil aggregate water stability. Here we used glass beads of different sizes to simulate different hyphal growing space conditions. With small beads (<106 μm; simulating a non-aggregated soil) fungal hyphal length was reduced over 80% compared to large beads (710–1180 μm; simulating an aggregated soil). Conversely, glomalin yield (immunoreactive protein) was more than seven times higher in the small bead growing space. The results challenge our thinking about soil aggregation as a consequence of general biological activity in soil, and uncover a new aspect of the biology of these ecologically important soil fungi.

Resonant acoustic measurement of vapor phase transport phenomenon in porous media

Diffusion of gases through porous media is commonly described using Fick’s law and is characterized by a gas diffusion coefficient modified by a media-specific tortuosity parameter. A phase-locked-loop resonance frequency tracker [J. Acoust. Soc. Am. 108, 2520 (2000)] has been upgraded with an insulated copper resonator and a bellows-sealed piston instrumented with an accelerometer. Average system stability (temperature divided by frequency squared) is about 180 ppm. Glass-bead-filled cores of different lengths are fitted into an o-ring sealed opening at the top of the resonator. The rate at which the tracer gas is replaced by air within the resonator is controlled by the core’s diffusion constant. Mean molecular weight of the gas mixture in the resonator is determined in real time from the ratio of the absolute temperature to the square of the fundamental acoustic resonance frequency. Molecular weight of the gas mixture is determined approximately six times per minute. Changes in the gas mixture concentration are exponential in time (within 0.1%) over nearly two decades in concentration. We will report diffusion constants for two different sizes of glass beads, in samples of five different lengths, using two different tracer gases, to establish the validity of this approach. [Work supported by ONR.]

Steady state dispersion of mono-size, binary and multi-size particles in a liquid fluidized bed classifier

The hydrodynamic model for a liquid–solid classifier, developed by Chen et al. (2001), is applied to the steady state dispersion of mono-size, binary and multi-size particles in a liquid fluidized bed classifier. For the binary and multi-size systems, the particles had different sizes but equal densities. The model was used to investigate the effects of different operating conditions—fluidizing liquid flowrate, feed voidage, feed flowrate, underflow discharge flowrate, breadth of particle size distribution in feed stream, height of cylindrical region of the classifier—on the voidages in the underflow discharge stream and the overflow stream from the classifier, as well as classifier efficiencies. The single fitted parameter, an axial dispersion coefficient, is either fitted for a single condition using measured voidages or concentrations, or is based on a correlation given in an earlier paper. Predictions from the model agree quite well with the experimental results obtained in five columns of diameter 191 mm having different geometries with water and glass beads of different sizes.

Extraction of fungal fatty acids for gas chromatography analysis

The standard method for the extraction of fatty acids from fungi recommended in association with commercially produced fatty acid analysis systems (MIDI Inc., Newark, Delaware) was compared with methods utilizing a Polytron homogenizer and vortexing with glass beads for disruption of fungal mycelia. The extraction efficiencies and variability were compared utilizing two isolates of Ceratocystis fagacearum, the causal agent of oak wilt. Using a Polytron homogenizer significantly reduced the fatty acid levels (61%) when compared to the standard method. Vortexing with glass beads (425–600 μm) increased the fatty acid levels (49%) and reduced variability (20%) when compared to the standard method. Different sizes of glass beads (150–212 μm, 425–600 μm, 710–1180 μm) did not yield significant differences in extraction efficiency with the fatty acid levels with 150–212 μm and 710–1180 μm being 71% and 59% compared to the use of 425–600 μm glass beads. The addition of 1 g glass beads/sample followed by vortexing for 2 min is easily adapted in any laboratory conducting fatty acid analysis without additional equipment. The reduction in the variability of samples would be extremely important when looking for minor changes in fatty acid percentages and composition. The standard recommended growth temperature (28 C) was decreased (22 C) for maximal growth of C. fagacearum. No significant differences were noted between the use of SDB and PDB except in the level of 14:0 fatty acid which was a minor component in the total levels of fatty acids (0.7 and 0.3%, respectively). However, growth of C. fagacearum on potato dextrose broth was 51.5% that obtained on Saubouraud dextrose broth. No significant differences were observed between the fatty acid profiles of C. fagacearum isolates from South Carolina, West Virginia, Ohio, Wisconsin and Texas utilizing the amended method.

Extraction of Fungal Fatty Acids for Gas Chromatography Analysis

The standard method for the extraction of fatty acids from fungi recommended in association with commercially produced fatty acid analysis sys- tems (MIDI Inc., Newark, Delaware) was compared with methods utilizing a Polytron homogenizer and vortexing with glass beads for disruption of fungal mycelia. The extraction efficiencies and variability were compared utilizing two isolates of Ceratocystis fagacearum, the causal agent of oak wilt. Using a Poly- tron homogenizer significantly reduced the fatty acid levels (61%) when compared to the standard meth- od. Vortexing with glass beads (425-600 rtm) in- creased the fatty acid levels (49%) and reduced var- iability (20%) when compared to the standard meth- od. Different sizes of glass beads (150-212 jLm, 425- 600 pLm, 710-1180 jum) did not yield significant dif- ferences in extraction efficiency with the fatty acid levels with 150-212 jim and 710-1180 JUm being 71% and 59% compared to the use of 425-600 Im glass beads. The addition of 1 g glass beads/sample fol- lowed by vortexing for 2 min is easily adapted in any laboratory conducting fatty acid analysis without ad- ditional equipment. The reduction in the variability of samples would be extremely important when look- ing for minor changes in fatty acid percentages and composition. The standard recommended growth temperature (28 C) was decreased (22 C) for maxi- mal growth of C. fagacearum. No significant differ- ences were noted between the use of SDB and PDB except in the level of 14:0 fatty acid which was a mi- nor component in the total levels of fatty acids (0.7

Effects of slip at the wall on the viscosity of suspensions with a polymeric matrix

The flow behavior of concentrated suspensions consisting of a Newtonian matrix (hydroxyl-terminated-polybutadiene, HTPB) mixed with two different sizes of aluminum powder (30% and above by volume) and two different sizes of glass beads (50% and above by volume) was investigated. The effects of the solid content, particle size, type of solid particle material, and the temperature on the shear stress and viscosity of the composite systems were studied. Slip at the wall was an important factor in suspensions with high filler content, large particle size, and measurements carried out at high temperatures requiring corrections for slip at the wall effects. Suspensions with filler contents of 50% and above by volume showed non-Newtonian behavior, whereas suspensions with smaller contents of filler were Newtonian. In most cases, the non-Newtonian suspensions were pseudoplastic at small shear rates, but dilatant at high shear rates. The dilatancy became evident only upon correction for slip at the wall. © 1999 John Wiley & Sons, Inc. Adv Polym Techn 18: 336–342, 1999

Slip velocity and slip layer thickness in flow of concentrated suspensions

The rheological characterization of highly filled suspensions consisting of a Newtonian matrix (hydroxyl-terminated polybutadiene), mixed with two different sizes of aluminum powder (30% and above by volume) and two different sizes of glass beads (50% and above by volume), was performed using a parallel disk rheometer with emphasis on the wall slip phenomenon. The effects of the solid content, particle size, type of solid particle material, and temperature on slip velocity and slip layer thickness were investigated. Suspensions of small particles of aluminum (mean diameter of 5.03 μm) did not show slip at any concentration up to the maximum packing fraction. However, suspensions of the other particles exhibited slip at the wall, at concentrations close to their maximum packing fraction. In these suspensions, the slip velocity increased linearly with the shear stress, and at constant shear stress, the slip velocity increased with increasing temperature. The slip layer thickness increased proportionally with increasing size of the particles for the glass beads. Up to a certain value of (filler content/maximum packing fraction), ϕ/ϕm, the slip layer thickness divided by the particle diameter, δ/DP, was 0, but it suddenly increased and reached a value that was independent of ϕ/ϕm and the temperature. On average, the ratio of δ/DP was 0.071 for aluminum and 0.037 for glass beads. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 515–522, 1998

Simulation of structural phenomena in mixed‐particle fluidized beds

AbstractA statistical mechanical simulation was developed and used to predict the macroscopic and microscopic behavior of fluidized beds. In particular, the model was used to study structural phenomena in liquid fluidized beds that contain a distribution of particle sizes and/or densities. Bed structural phenomena, such as density‐based and size‐based segregation, classification, expansion, inversion, and solids dispersion have all been successfully simulated. Experimental data for the segregation of glass beads of different sizes and different densities agree well with predictions made from the simulation (without adjustable parameters). Classification and dispersion simulations also show good agreement with experimental data.

Hydrodynamics and mass transfer in a suspended solid bubble column with polydispersed high density particles

Hydrodynamics and gas-liquid mass transfer are studied in a bubble and slurry bubble column. The investigations are made in a small scale (ID 0.1 m; height: 2 m) column using two batches of polydispersed and dense pyrite particles (ϱs = 4500kg/m3). These experiments were also made with glass beads of different sizes (38, 85 and 160 μm), to compare with literature results. The evolution of the gas holdup and the volumetric gas-liquid mass transfer coefficient with the particle diameter obtained in the case of glass beads indicates the existence of a critical particle diameter corresponding to the maximum values of these parameters.