Effect of Surface Roughness on Micro-channel Flow of Dilute Polymer Solutions

Ogata, Satoshi; Miyagi, Junya; Tsubone, Takafumi

doi:10.1678/rheology.44.131

Cited by 2 publications

(2 citation statements)

References 11 publications

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“…Ogata et al discussed effect of polymer chains near the wall on pressure drop in microchannel flows. 11) Moreover, previous studies have found that the elastic properties are based on the entanglement of the polymer chains in aqueous solutions. 26,27) Such entanglement is generated with higher overlap concentrations (PEO; 1600 ppm, 28) PAA; 93 ppm 29) ).…”

Section: Discussionmentioning

confidence: 99%

“…6) Hidema et al used an abrupt-contraction syringeshaped channel to measure elongational viscosity, 7) and also analyzed two-dimensional turbulence in several types of dilute polymer solutions, and reported that the laminarization of turbulence due to elongational viscosity was dependent on the flexibility of the polymer chains. [8][9][10] Ogata et al investigated the effect of wall surface roughness on pressure drop in micro-channel flows of dilute polymer solutions 11) and found that the hydrophobic and hydrophilic walls exhibited different pressure drops. Hasegawa et al measured elastic stresses via the jet thrust (JT) and jet reaction of solutions flowing from small orifices.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Relationship between Flow Properties and Elastic Stresses of Dilute and Ultra-Dilute Polymer Solutions Passing through Small Apertures

Ushida

Sato

Narumi

et al. 2021

J. Soc. Rheol., Jpn

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The Weissenberg number, defined as the product of relaxation time and strain rate, reflects the ratio of elastic forces to viscous forces in a viscoelastic flow. Thus, at high strain rate based on a small (micrometer-scale) characteristic length, elastic properties are important for understanding the flow properties of dilute (100 ppm and 10 ppm) and ultra-dilute (1 ppm) aqueous polymer solutions. However, the very small elasticity and high strain rate make it difficult to measure the elastic properties precisely. In this study, flow properties and elastic stresses were investigated for dilute and ultra-dilute polymer solutions flowing through small slits with characteristic lengths of between 122 µm and 1.1 mm. The pressure drop (PD) and jet thrust (JT) for polyethylene oxide (PEO) and polyacrylamide (PAA) solutions were measured from their flow properties and elastic stresses, respectively. The pressure difference upon passing through a small slit and the momentum issuing from the slit at a constant flow rate were measured as the PD and JT, respectively. Although the measured PD of water and silicone oil agreed with the numerical predictions of the Navier-Stokes equation, the resultant PDs for all PEO samples were less than those for water and silicone oil. Similar results were obtained for all PAA samples; the PDs for aqueous solutions of 100 ppm, 10 ppm, and 1 ppm PAA were reduced. The JT values were also smaller than those for water and silicone oil. Even though ultra-dilute solutions were used, it is interesting that the PDs and JTs were reduced. Furthermore, to understand the experimental results, elastic stress was determined from the JT. The calculated elastic stress depended on the mean velocity. The relationship between the flow properties and the elastic properties was clarified, and the effect of surface tension was described by estimating the capillary number.

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