A Viscometer for Measurements during Thixotropic Recovery. Results with a Compounded Latex

1947 ◽  
Vol 20 (2) ◽  
pp. 585-596
Author(s):  
M. Mooney
Keyword(s):  
Hollow Cylinder ◽  
Relative Viscosity ◽  
Annular Channel ◽  
Outer Wall ◽  
Solid Particles ◽  
Shearing Stress ◽  
Coagulation Rate ◽  
Constant Torque ◽  
Torsion Suspension ◽  
Percentage Volume

Abstract A viscometer is described for measuring the viscosity of a liquid immediately after an abrupt reduction of the shearing stress to a very low value. A hollow cylinder on a torsion suspension is immersed in the liquid contained in a narrow annular channel. The inner wall of the channel is rotatable with respect to the outer wall, and by this rotation the liquid is stirred or sheared. After the stirring is stopped, the viscosity is measured by recording photographically the rotation of the hollow cylinder, driven by a nearly constant torque applied through the torsion suspension. Measurements were made on a commercial compounded rubber latex containing 47.5 per cent of total solids. Immediately after stirring, the latex is a Newtonian liquid with a viscosity of 0.05 poise. Thereafter the viscosity increases at an initial rate and to an ultimate value, both of which decrease as the shearing stress for measuring the viscosity is increased. The steady viscosity is attained approximately in 10 seconds. The observed extremes in steady viscosity were 11 and 0.5 poise, corresponding to the shearing stresses 1.3 and 10.7 dynes per sq. cm. The experimental data are fitted approximately by theoretical curves based on these assumptions. All aggregates of solid particles are broken up by the stirring. During subsequent thixotropic recovery, loose aggregates are formed which contain considerable trapped water. The rate of aggregation follows Smoluchowski's theory of slow coagulation, but both the coagulation rate constant and the percentage volume of water in the coagulates vary with the applied shearing stress. The relative viscosity of the suspension of aggregates follows an empirical law based on Eilers' data on aqueous suspensions of bitumen spheres.

Numerical Investigation on Heat Transfer to Supercritical CO2 in Vertical Annular Channel

2016 ◽  
Author(s):  
Zhenxing Zhao ◽  
Jun Wu ◽  
Fan Bai ◽  
Qi Xiao ◽  
Chunhui Dai ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Supercritical Fluid ◽  
Annular Channel ◽  
Outer Wall ◽  
Wall Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Heat Transfer Deterioration ◽  
Flow And Heat Transfer ◽  
Wall Heating

The special fluid flow and heat transfer characteristics of supercritical CO2 in a vertical annular channel have been numerically investigated. The AKN k-ε model was selected to model the turbulent flow and heat transfer of supercritical fluid. The three heating types were individual outer-wall heating, simultaneous outer/inner walls heating and outer-wall heating (inner-wall cooling) separately. The local heat transfer coefficients were obtained to investigate the influence of inner-wall thermal boundary conditions, supercritical fluid mass flux, fluid temperature and flow direction on outer-wall heat transfer phenomenon. The mechanisms of abnormal heat transfer and primary influence factors were analyzed by the detailed information on the flow, turbulence and thermal fields. When the supercritical fluid is in the large-property-variation (LPV) region and flows upward, the inner-wall thermal boundary condition obviously affects the heat transfer characteristics of outer wall. When supercritical fluid flows downward, the inner-wall boundary condition hardly affects the heat transfer phenomena of outer wall. The increase of inner-wall heating heat flux will result in the larger deterioration region and heat transfer decline on outer wall when the other conditions remain unchanged. When the heat transfer deterioration also appears on the inner wall with the increase in the inner-wall heat flux, the outer-wall heat transfer no longer decreases, but the deterioration region abruptly increases. However, as inner-wall cooling heat flux increases, the heat transfer deterioration phenomenon on outer wall will weaken gradually.

Natural Convective Heat Transfer of Water-in-FC72 Nanoemulsion Fluids

2008 ◽  
Author(s):  
Zenghu Han ◽  
Bao Yang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Hydrodynamic Interaction ◽  
Convective Heat Transfer Coefficient ◽  
Relative Viscosity ◽  
Solid Particles ◽  
Water Loading

The use of SOLID-particles has long been a common way of increasing fluid thermal conductivity. In this paper, nanoemulsion fluids—dispersions of LIQUID-nanodroplets—are proposed. As an example, water-in-FC72 nanoemulsion fluids are developed, and their thermophysical properties and impact on natural convective heat transfer are investigated experimentally. A significant increase in thermal conductivity—up to 52% for 12vol% of water nanodroplets (or 7.1 wt%)—is observed in the fluids. The enhancement in conductivity and viscosity of the fluids is found to be nonlinear with water loading, indicating an important role of the hydrodynamic interaction and aggregation of nanodroplets. However, the relative viscosity is found to be about two times the relative conductivity if compared at the same water loading. The presence of water nanodroplets is found to systematically increase the natural convective heat transfer coefficient in these fluids, in contrast to the observation in several conventional nanofluids containing solid nanoparticles.

Turbulent Heat Transfer Studies in Annulus With Inner Cylinder Rotation

1977 ◽  
Vol 99 (1) ◽  
pp. 12-19 ◽  
Author(s):  
T. M. Kuzay ◽  
C. J. Scott
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Annular Channel ◽  
Outer Wall ◽  
Temperature Fields ◽  
Turbulent Heat Transfer ◽  
Experimental Investigations ◽  
Turbulent Heat ◽  
Radial Temperature ◽  
Axial Temperature

Experimental investigations of turbulent heat transfer are made in a large-gap annulus with both rotating and nonrotating inner cylinder. The vertical annular channel has an electrically heated outer wall; the inner wall is thermally and electrically insulated. The axial air flow is allowed to develop before rotation and heating are imparted. The resulting temperature fields are investigated using thermocouple probes located near the channel exit. The wall heat flux, wall axial temperature development, and radial temperature profiles are measured. For each axial Reynolds number, three heat flux rates are used. Excellent correlation is established between rotational and nonrotational Nusselt number. The proper correlation parameter is a physical quantity characterizing the flow helix. This parameter is the inverse, of the ratio of axial travel of the flow helix in terms of hydraulic diameter, per half revolution of the spinning wall.

scholarly journals CFD Modeling of Particulates Erosive Effect on a Commercial Scale Pipeline Bend

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Vahid Abdolkarimi ◽  
Rasool Mohammadikhah
Keyword(s):  
Computational Model ◽  
Size Distribution ◽  
Erosion Rate ◽  
Gas Flow ◽  
Outer Wall ◽  
Solid Particles ◽  
Cfd Modeling ◽  
Dynamics Modeling ◽  
Particles Size Distribution ◽  
Erosive Effect

The computational fluid dynamics modeling of solid particles hydrodynamic based on the Lagrangian framework for diluted solid-gas flow through 90° gas pipeline bend is carried out to discover the effect of particles size distribution on particles flow pattern and their erosive effect on the bend. Particles size distribution has been obtained experimentally by measuring the sizes of solid particles that are flowing through the gas pipelines of Aghajari gas booster station. Also the erosion rate at the outer wall of the bend is predicted. The pipeline bend under study has a pipe diameter of 56 inches and ratios of the bend radius of the curvature to the pipeline diameter of 1.5. For the validation of computational model, firstly, the computational modeling is performed for a published experimental solid-gas flow data. The computational results include radial gas velocity and radial particle velocity profiles on planes which are at different angles through the bend. The comparison between the predicted numerical results and similar experimental data proves that the predictions of the computational model are acceptable. Finally, the particles' size distributions on each plane through the bend and the erosion rate on the outer wall of the bend have been obtained. The maximum rate of erosion is found to be 3.2 nm/s, occurring between 40 and 65° of the bend.

Effects of Applying a Stochastic Rebound Model in Erosion Prediction of Elbow and Plugged Tee

2002 ◽  
Author(s):  
Xianghui Chen ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi
Keyword(s):  
Prediction Model ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Outer Wall ◽  
Stochastic Approach ◽  
Solid Particles ◽  
Gas Industry ◽  
Erosion Prediction ◽  
Before And After ◽  
Experimental Findings

Solid particle erosion is a complex phenomenon that depends on many factors such as particle and fluid characteristics, type of material being eroded, and flow geometry. Fittings used in the oil and gas industry such as elbows are susceptible to erosion when solid particles are present in the flow. The momentum of particles carries them across streamlines and the particles impinge the outer wall of the elbow resulting in erosion damage. In an erosive environment, plugged tees are commonly used instead of elbows to reduce the erosion especially where space considerations are important and long-radius elbows can not be used. However, it is unclear how much of a reduction in erosion occurs by replacing an elbow with a plugged tee. In order to compare the erosion in an elbow and a plugged tee exposed to the same flow conditions, a CFD-based erosion prediction model is applied. The model has three primary steps: flow modeling, particle tracking, and applying erosion equations. The results from the model agree with experimental findings for the elbow geometry. However, the simulation results for erosion rate generated for the plugged tee requires a stochastic approach. Results obtained with the erosion prediction model before and after this modification are shown.

Experimental Investigations of Steady and Pulsatile Laminar Flow in a 90° Branch

1977 ◽  
Vol 44 (3) ◽  
pp. 372-377 ◽  
Author(s):  
F. F. Mark ◽  
C. B. Bargeron ◽  
O. J. Deters ◽  
M. H. Friedman
Keyword(s):  
Aspect Ratio ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Outer Wall ◽  
Experimental Investigations ◽  
Two Dimensional ◽  
Shearing Stress ◽  
Velocity Measurements ◽  
Good Agreement ◽  
Flow Velocities

Velocity measurements are reported for steady and unsteady flow in a rectangular cross-section Y-branch of high aspect ratio. Good agreement is found between the experimental results and two-dimensional calculations. Emphasis is placed on flow velocities near and parallel to the outer wall inasmuch as their gradients are proportional to wall shearing stress which may be of influence in atherogenesis. Large variation in flow velocities and hence shearing stress are found in the immediate vicinity of the corner. The results in this region could support theories which propose either high or low shearing stress as an important consideration in the etiology of arteriosclerosis.

scholarly journals Rheology of three-phase suspensions determined via dam-break experiments

2021 ◽  
Vol 477 (2254) ◽  
Author(s):  
Janine Birnbaum ◽  
Einat Lev ◽  
Ed W. Llewellin
Keyword(s):  
Capillary Number ◽  
Relative Viscosity ◽  
Shear Thickening ◽  
Dam Break ◽  
Solid Particles ◽  
Rheological Models ◽  
Volcanic System ◽  
Three Phase ◽  
Inertial Regime

Three-phase suspensions, of liquid that suspends dispersed solid particles and gas bubbles, are common in both natural and industrial settings. Their rheology is poorly constrained, particularly for high total suspended fractions (≳0.5). We use a dam-break consistometer to characterize the rheology of suspensions of (Newtonian) corn syrup, plastic particles and CO 2 bubbles. The study is motivated by a desire to understand the rheology of magma and lava. Our experiments are scaled to the volcanic system: they are conducted in the non-Brownian, non-inertial regime; bubble capillary number is varied across unity; and bubble and particle fractions are 0 ≤  ϕ gas  ≤ 0.82 and 0 ≤  ϕ solid  ≤ 0.37, respectively. We measure flow-front velocity and invert for a Herschel–Bulkley rheology model as a function of ϕ gas , ϕ solid , and the capillary number. We find a stronger increase in relative viscosity with increasing ϕ gas in the low to intermediate capillary number regime than predicted by existing theory, and find both shear-thinning and shear-thickening effects, depending on the capillary number. We apply our model to the existing community code for lava flow emplacement, PyFLOWGO, and predict increased viscosity and decreased velocity compared with current rheological models, suggesting existing models may not adequately account for the role of bubbles in stiffening lavas.

Architecture of Radiolitid Rudist (Mollusca) Shell-Wall Structures and its Phylogenetic Implications

1975 ◽  
Vol 33 ◽  
pp. 686-687
Author(s):  
David H. Sturm ◽  
Bob F. Perkins
Keyword(s):  
Phylogenetic Relationships ◽  
Outer Wall ◽  
Shell Microstructure ◽  
Shell Wall ◽  
Wall Structures ◽  
Phylogenetic Implications ◽  
Cellular Wall ◽  
Superfamily Analysis ◽  
Central Texas

Each of the seven families of rudists (Mollusca, Bivalvia, Hippuritacea) is characterized by distinctive shell-wall architectures which reflect phylogenetic relationships within the superfamily. Analysis of the complex, calcareous, cellular wall of the attached valve of the radiolite rudist Eoradiolites davidsoni (Hill) from the Comanche Cretaceous of Central Texas indicates that its wall architecture is an elaboration of the simpler monopleurid rudist wall and supports possible radiolite-monopleurid relationships.Several well-preserved specimens of E. davidsoni were sectioned, polished, etched, and carbon and gold coated for SEM examination. Maximum shell microstructure detail was displayed by etching with a 0.7% HC1 solution from 80 to 100 seconds.The shell of E. davidsoni comprises a large, thick-walled, conical, attached valve (AV) and a small, very thin, operculate, free valve (FV) (Fig. 1a). The AV shell is two-layered with a thin inner wall, in which original structures are usually obliterated by recrystallization, and a thick, cellular, outer wall.

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