Relaxation Behavior of a Drag-Reducing Cationic Surfactant Solution

Experimental Thermal and Fluid Science

Komoda

2015

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Section: Measurements Of Rheological Characteristicssupporting

confidence: 76%

Flow characteristics in a micro-cavity swept by a visco-elastic fluid

Experimental Thermal and Fluid Science

Komoda

2015

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“…Zheng et al 14) revealed the reconstruction from rod-like micelles to vesicles after the stress release. Suzuki et al 13) reported the third relaxation time corresponds to this reconstruction. Thus, the first or the second relaxation time was adopted for defining the Weissenberg number as related to the elasticity of the fluids.…”

Section: Flow Visualization and Pressure Loss Measurementmentioning

confidence: 75%

“…Figure 1 shows the effect of the molar ratio of counter-ions to the relaxation times obtained in the previous study. 13) As shown in the figure, there exist three relaxation times from 0.80 to 2.0 of the molar ratio of counterions. The longest relaxation disappears when x is lower than 0.50 or higher than 3.0.…”

Section: Rheological Characteristicsmentioning

confidence: 94%

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Effects of the Molar Ratio of Counter-Ions on Flow Characteristics of Surfactant Solutions Sweeping Cavities

Sato

et al. 2016

J. Soc. Rheol., Jpn

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An experimental study has been performed in order to investigate the optimum rheological characteristics for a technique of heat transfer augmentation in a cavity between ribs mounted in parallel plates. The rheological characteristics of visco-elastic fluid were changed by controling the molar ratio of counter-ion to a cationic surfactant. Flow visualization experiments and pressure loss measurements were conducted in the range of solvent Reynolds number from 100 to 2,500 and in the range of molar ratio from 0.50 to 10. Under this condition, the zoro-shear Reynolds number and the Weissenberg number ranged from 2.01 to 120 and from 1.94 × 10 -2 to 9.15, respectively.From the results, flow penetration into the cavity occurred in the cases from 1.5 to 5.0 of molar ratio of counter-ions. However, the pressure loss became large in the cases when the remarkable Barus effect can be observed. On the other hand, the pressure loss became almost the same as that of water in the case when the molar ratio of counter-ions was set at 5.0. From this, it was concluded that the optimum fluid for the heat transfer augmentation in a cavity is required to have suitable elasticity and low viscosity as the molar ratio of counter-ions is set around 5.0.

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“…Suzuki et al 19) investigated the relaxation behaviour of the surfactant system and analyzed with a triple exponential Maxwell model as follows. [s] are the relaxation times for the respective relaxation behaviours defined as t r1 < t r2 < t r3 .…”

Section: Rheological Characteristicsmentioning

confidence: 99%

Velocity Fields around the Bulge Structure Observed in a Cavity Swept by a Visco-Elastic Fluid

Tanomura

et al. 2018

J. Soc. Rheol., Jpn

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