Formation Process of Taylor Cells of a Surfactant Solution

2002 ◽  
Author(s):  
Keizo Watanabe ◽  
Tsukasa Takayama ◽  
Satoshi Ogata
Keyword(s):  
Formation Process ◽  
Tap Water ◽  
Surfactant Solution ◽  
Cylinder Wall ◽  
Number Range ◽  
Taylor Vortices ◽  
Surfactant Solutions ◽  
Flow Test ◽  
Stabilizing Effect ◽  
Shear Induced Structure

The flow of surfactant solutions between two coaxial cylinders was investigated using the laser-induced-fluorescence flow visualization technique to clarify the effect of drag-reducing additives on the formation process of Taylor cells in Taylor-Couette flow. Test fluids were Ethoquad O/12 10, 50 and 100 ppm surfactant solutions. In the Taylor number range of, 1.2×105 ≤ Ta ≤ 7.1×105, tap water and 10 ppm surfactant solution flows consisted of Taylor vortices and much smaller Go¨rtler vortices at the rotating inner cylinder wall. However, in 50 and 100 ppm surfactant solutions, Taylor vortices are not apparent and Go¨rtler vortices are collapsed. Measurement of the wavelength of Go¨rtler vortices led to the conclusion that surfactant solutions have a stabilizing effect on Go¨rtler instabilities. This effect depends on the concentration of surfactant solutions, and becomes considerable with increasing acceleration of the rotating inner cylinder. By considering the experimental results for the surfactant solutions without counterions, in which Taylor cells were not formed, it was shown that the increase in the local field viscosity based on the shear-induced structure of the surfactant solutions has a stabilizing effect on Go¨rtler instability.

Drag Reduction of the Flow Past a Circular Cylinder in Surfactant Solution

2001 ◽  
Author(s):  
Satoshi Ogata ◽  
Keizo Watanabe
Keyword(s):  
Circular Cylinder ◽  
Drag Reduction ◽  
Sodium Salicylate ◽  
Tap Water ◽  
Pressure Coefficient ◽  
Surfactant Solution ◽  
Reduction Ratio ◽  
Number Range ◽  
Surfactant Solutions ◽  
Maximum Drag Reduction

Abstract The flow around a circular cylinder in surfactant solution was investigated experimentally by measurement of the pressure and velocity profiles in the Reynolds number range 6000 < Re < 50000. The test surfactant solutions were aqueous solutions of Ethoquad O/12 (Lion Co.) at concentrations of 50, 100 and 200 ppm, and sodium salicylate was added as a counterion. It was clarified that the pressure coefficient of surfactant solutions in the range of 10000 < Re < 50000 at the behind of the separation point was larger than that of tap water, and the separation angle increased with concentration of the surfactant solution. The velocity defect in surfactant solutions behind a circular cylinder was smaller than those in tap water. The drag coefficients of a circular cylinder in surfactant solutions were smaller than those of tap water in the range 10000 < Re < 50000, and no drag reduction occurred at Re = 6000. The drag reduction ratio increased with increasing concentration of surfactant solution. The maximum drag reduction ratio was approximately 35%.

Flow of Surfactant Solutions Past a Circular Cylinder

2004 ◽  
Author(s):  
Yoshihisa Osano ◽  
Satoshi Ogata ◽  
Keizo Watanabe
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Drag Reduction ◽  
Drag Coefficient ◽  
Tap Water ◽  
Surfactant Solution ◽  
Number Range ◽  
Surfactant Solutions ◽  
Reynolds Number Range ◽  
Trade Name

To clarify the effects of surfactant solutions on the drag coefficient of a circular cylinder, the flow past a circular cylinder was investigated in the Reynolds number range of 10 to 7,000 by measuring the drag and by visualizing flow. In addition, the flow pattern was simulated numerically to examine the effect of the viscoelasticity of the surfactant solution. Six cylinders with diameters between 2 and 20 mm were tested, and the ratio of length to diameter (l/d) was 12~48. The test surfactant solutions were aqueous solutions of oleyl-methyldihydroxyethyl ammonium chloride (trade name: Ethoquad O/12) in the concentration range of 50 to 200 ppm and sodium salicylate was added as a counterion. It was clarified that the drag coefficient of surfactant solutions increases comparing with that of tap water in the Reynolds number range of 1,000 < Re 3,000 and drag reduction occurs when Re > 3,000 for a cylinder diameter of 20 mm. The maximum drag reduction ratio was approximately 55% for 200 ppm solution at Re = 7,000. The flow visualization results showed that the drag of surfactant solutions increases because of the existence of the wide stagnant zone around the cylinder. This zone disappeared in the Reynolds number range in which drag reduction occurred. In addition, the width of the wake of surfactant solutions decreases compared with that of tap water, and the Ka´rma´n vortex street is not found. These effects seem to be due to the elasticity caused by the micellar network in surfactant solution.

Drag of a Circular Cylinder in Surfactant Solutions at Intermediate Reynolds Number Range

2003 ◽  
Author(s):  
Satoshi Ogata ◽  
Keizo Watanabe ◽  
Yoshihisa Osano
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Drag Reduction ◽  
Drag Coefficient ◽  
Tap Water ◽  
Surfactant Solution ◽  
Number Range ◽  
Surfactant Solutions ◽  
Cylinder Diameter ◽  
Reynolds Number Range

To clarify the behavior of the drag coefficient of a circular cylinder in the intermediate Reynolds number range, the flow around a circular cylinder in surfactant solutions was investigated experimentally by measurement of the drag in the Reynolds number range of 3 × 102 to 7 × 103. The experiments were performed in a vertical re-circulating water tunnel. The drag coefficient was measured using an apparatus which could measure the drag acting on the circular cylinder directly. Five cylinders of diameter d = 5, 7, 10, 13 and 20 mm were tested, the ratios of length to diameter (l/d) were 12, 24 and 48. The test surfactant solutions were aqueous solutions of Ethoquad O/12 at concentrations of 50, 100 and 200 ppm, and sodium salicylate was added as a counterion. It was clarified that the drag coefficient of the cylinder in surfactant solutions increased comparing that in tap water in the Reynolds number lower approximately 103 < Re < 3 × 103. According to the increase of the Reynolds number, the drag coefficient decreased. When Reynolds number exceeded approximately 103 < Re < 3 × 103, the drag coefficient in surfactant decreased in comparison with that in tap water finally. In other ward, the drag reduction occurred in this Reynolds number range. The maximum drag reduction was about 55% for 200 ppm solution and 20mm diameter at Re ≅ 7 × 103. The value of the drag coefficient in surfactant solutions was dependent on not only (l/d) but also cylinder diameter. The drag coefficient increased with increasing cylinder diameter. The increase in the concentration of surfactant solution emphasized the characteristics of drag reduction and drag increase.

Drag Reduction of Polymer Solutions in a Pipe With a Highly Water-Repellent Wall

1999 ◽  
Author(s):  
Keizo Watanabe ◽  
Hiroshi Udagawa
Keyword(s):  
Pressure Drop ◽  
Laminar Flow ◽  
Drag Reduction ◽  
Polymer Solutions ◽  
Tap Water ◽  
Acrylic Resin ◽  
Water Repellent ◽  
Number Range ◽  
Surfactant Solutions ◽  
Laminar And Turbulent Flow

Abstract By applying a highly water-repellent wall pipe in the drag reduction of polymer solutions, a flow system in which drag reduction is obtained in both laminar and turbulent flow ranges has been realized. Experiments were carried out to measure the pressure drop in pipes with a highly water-repellent wall and an acrylic resin wall by means of a pressure transducer. The diameter of the pipe was 6mm. The polymer solutions tested were PE015 aqueous solutions in the concentration range of 30ppm∼1000ppm. The drag reduction ratio for laminar flow was about 11∼15%. To understand this effect, the pressure drop was measured by using surfactant solutions and degassed water, and by pressurizing tap water in the pipeline. It was shown that the laminar drag reduction does not occur in the case of surfactant solutions although degassed water and pressurizing tap water in the pipeline have no effect on the reduction. In the laminar flow range, the friction factor of a power-law fluid with fluid slip was analyzed by applying the modified boundary condition on fluid slip at the pipe wall, and the analytical results agree with the experimental results in the low Reynolds number range.

Flow Characteristics of a Rotating Disk in Surfactant Solutions

2000 ◽  
Author(s):  
Satoshi Ogata ◽  
Keizo Watanabe
Keyword(s):  
Boundary Layer ◽  
Tap Water ◽  
Flow Direction ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Rotating Disk ◽  
Circular Pipe ◽  
Number Range ◽  
Surfactant Solutions ◽  
Momentum Integral

Abstract Recently, considerable interest has developed in surfactant additives for use in district heating and cooling systems to lower the pumping energy requirement. Many studies in the case of surfactant solutions have been done for the flow behavior in a circular pipe. However, few studies have been conducted on flow near a rotating disk in surfactant solutions. In this paper, the flow characteristics near an enclosed rotating disk in surfactant solutions were studied by applying flow visualization techniques and analyzed by applying the momentum integral equations which are related to the three boundary layer problem. The test surfactant solution was Ethoquad 0/12 with sodium salicylate at a concentration of 200ppm and a temperature of 18°C. The flow patterns were obtained at Re = 2.5×105 and 3.5×105 so that the Reynolds number range corresponds with the transition region to turbulent flow in the boundary layer on the rotating disk for Newtonian fluids. Consequently, it has been clarified that the amplitude of the circular vortex on the rotating disk was reduced and the flow direction near the disk was turned outward to the circumferential direction comparing with that of tap water. In additional, the limiting maximum drag reduction asymptote for a moment coefficient of a rotating disk was obtained by applying the momentum integral equation for drag-reducing solutions based on previous papers on circular pipe flow.

Effect of Surfactant Additives on a Boundary Layer on a Flat Plate

2005 ◽  
Author(s):  
Satoshi Ogata ◽  
Takeshi Fujita
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Velocity Profile ◽  
Flat Plate ◽  
Newtonian Fluid ◽  
Surfactant Concentration ◽  
Shape Parameter ◽  
Tap Water ◽  
Number Range ◽  
Surfactant Solutions

The effect of surfactant solutions on the boundary layer over a flat plate has been investigated in the Reynolds number range of approximately Re < 153,000. Experiments were carried out by measuring the velocity profile using a PIV system. Surfactant solutions tested were aqueous solutions of oleyl-bihydroxyethyl methyl ammonium chloride (Ethoquad O/12) in the concentration range of 50 to 500 ppm, to which sodium salicylate was added as a counterion. It was clarified that the boundary layer thickness of surfactant solutions increases significantly near the leading edge comparing with that of tap water, and parallelly develops in that obtained by the Blasius equation. For lower surfactant concentration (50 and 200 ppm) the velocity profile near the wall is distributed between that of laminar flow and turbulent flow for Newtonian fluid. When the Reynolds number increases, the velocity profile gradually increases from the outer edge of the boundary, and approaches the turbulent velocity profile of Newtonian fluid. For higher surfactant concentration (500 ppm), the velocity profile shows large S-shape. The velocity profile does not change very much, even if the Reynolds increases. The shape parameter with surfactant solutions decreases slightly comparing that of tap water at Re < 92,000, The value of shape parameter H with surfactant solution shows 1.66 < H < 2.32.

scholarly journals Numerical Investigation of the Three-Dimensional Pressure Distribution in Taylor Couette Flow

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
David Shina Adebayo ◽  
Aldo Rona
Keyword(s):  
Dynamic Pressure ◽  
Three Dimensional ◽  
Mechanical Efficiency ◽  
Navier Stokes ◽  
Cylinder Wall ◽  
Rotating Shaft ◽  
Number Range ◽  
Taylor Vortices ◽  
Delivery Pipe ◽  
Radial Outflow

An investigation is conducted on the flow in a moderately wide gap between an inner rotating shaft and an outer coaxial fixed tube, with stationary end-walls, by three-dimensional Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD), using the realizable k−ε  model. This approach provides three-dimensional spatial distributions of static and dynamic pressures that are not directly measurable in experiment by conventional nonintrusive optics-based techniques. The nonuniform pressure main features on the axial and meridional planes appear to be driven by the radial momentum equilibrium of the flow, which is characterized by axisymmetric Taylor vortices over the Taylor number range 2.35×106≤Ta≤6.47×106. Regularly spaced static and dynamic pressure maxima on the stationary cylinder wall follow the axial stacking of the Taylor vortices and line up with the vortex-induced radial outflow documented in previous work. This new detailed understanding has potential for application to the design of a vertical turbine pump head. Aligning the location where the gauge static pressure (GSP) maximum occurs with the central axis of the delivery pipe could improve the head delivery, the pump mechanical efficiency, the system operation, and control costs.

A New Dynamic Wettability-Alteration Model for Oil-Wet Cores During Surfactant-Solution Imbibition

SPE Journal ◽  
2013 ◽  
Vol 18 (05) ◽  
pp. 818-828 ◽  
Author(s):  
M. Hosein Kalaei ◽  
Don W. Green ◽  
G. Paul Willhite
Keyword(s):  
Experimental Data ◽  
Oil Recovery ◽  
History Matching ◽  
Mechanistic Model ◽  
Surfactant Solution ◽  
Experimental Tests ◽  
Quantitative Agreement ◽  
Wettability Alteration ◽  
Porous Rock ◽  
Surfactant Solutions

Summary Wettability modification of solid rocks with surfactants is an important process and has the potential to recover oil from reservoirs. When wettability is altered by use of surfactant solutions, capillary pressure, relative permeabilities, and residual oil saturations change wherever the porous rock is contacted by the surfactant. In this study, a mechanistic model is described in which wettability alteration is simulated by a new empirical correlation of the contact angle with surfactant concentration developed from experimental data. This model was tested against results from experimental tests in which oil was displaced from oil-wet cores by imbibition of surfactant solutions. Quantitative agreement between the simulation results of oil displacement and experimental data from the literature was obtained. Simulation of the imbibition of surfactant solution in laboratory-scale cores with the new model demonstrated that wettability alteration is a dynamic process, which plays a significant role in history matching and prediction of oil recovery from oil-wet porous media. In these simulations, the gravity force was the primary cause of the surfactant-solution invasion of the core that changed the rock wettability toward a less oil-wet state.

Surfactant Effects on Picloram Adsorption by Soils

Weed Science ◽  
1976 ◽  
Vol 24 (6) ◽  
pp. 549-552 ◽  
Author(s):  
J. D. Gaynor ◽  
V. V. Volk
Keyword(s):  
Organic Matter ◽  
Cationic Surfactant ◽  
Anionic Surfactant ◽  
Organic Matter Content ◽  
Clay Content ◽  
Surfactant Solution ◽  
Matter Content ◽  
Adsorption Sites ◽  
Surfactant Solutions ◽  
Extractable Al

The effects of soil organic matter, clay, extractable Al, cation exchange capacity, and pH on the adsorption of picloram (4-amino-3,5,6-trichloropicolinic acid) from aqueous and surfactant solutions were investigated. Linear adsorption isotherms for the soils were obtained with the Freundlich equation. Of the five soil properties investigated, Freundlich K values correlated with extractable Al and clay content. Picloram adsorption from aqueous solutions and from the non-ionic and anionic surfactant solutions was greater on the soils at pH 5 than at pH 7. The anionic surfactant competed with picloram for adsorption sites on the soils at pH 5. Picloram adsorption from solutions containing 0.1 and 1% cationic surfactant was greater than that from aqeuous and anionic and nonionic surfactant solutions. Picloram adsorption from the 10% cationic surfactant solution was similar on soils with pH 5 and 7 and increased with decreased organic matter content.

Boiling of Water and Surfactants in Confined Space

2008 ◽  
Author(s):  
G. Hetsroni
Keyword(s):  
Heat Flux ◽  
High Speed ◽  
Video Recording ◽  
Surfactant Solution ◽  
Time Behavior ◽  
Gap Size ◽  
Confined Space ◽  
Annular Channels ◽  
Surfactant Solutions ◽  
Nucleation Sites

Natural convection boiling of water and surfactant solutions at atmospheric pressure in narrow horizontal annular channels was studied experimentally. The Alkyl (8–16) Glucoside with molecular weight of 390 g/mol was used in the experiments. It is a nonionic surfactant with negligible environmental impact. The length of the horizontal channels was 24 mm and 36 mm, the gape size was in the range of 0.45–3.7 mm, the heat flux was in the range of 20–500 kW/m2, the concentration of surfactant solutions was varied from 10 to 600 ppm. The gap size of the vertical channels was changed in the range of 1–80 mm. The flow pattern was visualized by high-speed video recording to identify the different regimes of boiling of water and surfactant solutions with different concentrations. At heat flux q<100 kW/m2 the rapid growth of elongated bubble was observed in the water. The rapid bubble growth pushes the liquid-vapor interface on both open sides of the channel. When a bubble departs from a nucleus cavity, its cavity is then recovered by liquid, and next bubble will appear on the heated tube after a certain interval. The behavior of the long vapor bubbles occurring in small size annular channels is not similar to annular flow with intermitted slugs between two vapor trains. Surfactant solution promotes activation of nucleation sites in a clustered mode. The cluster contains a number of small bubbles, the location of nucleation sites and time behavior of each bubble cannot be traced exactly. At higher values of heat flux coalescence process was observed during boiling of water and surfactant solutions. For water boiling in horizontal channels at Bond numbers Bo<1 the CHF in restricted space is lower than that in unconfined apace. This effect increases with increasing the channel length. For water at Bond number Bo = 1.52, boiling can be considered as unconfined. Additive of surfactant led to enhancement of heat transfer compared to water boiling in the same gap size, however, this effect decreased with decreasing gap size. For the same gap size, CHF in surfactant solutions was significantly lower than that in water. Hysteresis was observed for boiling in degraded surfactant solutions.

Sign in / Sign up

Export Citation Format

Share Document