The Viscosity Distribution around a Rising Bubble in Shear-thinning Non-newtonian Fluids
نویسندگان
چکیده
The viscosity distribution of the liquid around a rising bubble in carboxymethyl cellulose (CMC) aqueous solutions was measured experimentally by particle image velocimetry (PIV). The effect of the concentration of CMC solutions on the viscosity distribution around a bubble and the coupling relations between the viscosity field, flow field and shear stress field were also studied. Results indicated that the specific viscosity (non-dimensionalized by 0 η ) decreases with the increase in CMC solution concentration due to a shear thinning effect. Within the experimental range, similar viscosity distributions of liquids around a rising bubble were found: a hollow cylindrical low viscosity region around the bubble wake and a high viscosity region in the central bubble wake.
منابع مشابه
Time-periodic Electroosmotic Flow of Non-newtonian Fluids in Microchannels
The alternating current electroosmotic flow of a non-Newtonian power-law fluid is studied in a circular microchannel. A numerical method is employed to solve the non-linear Poisson-Boltzmann and the momentum equations. The main parameters which affect the flow field are the flow behavior index, the dimensionless zeta potential and the dimensionless frequency. At very low dimensionless frequenci...
متن کاملModels of non-Newtonian Hele-Shaw flow.
We study the Saffman-Taylor instability of a non-Newtonian fluid in a Hele-Shaw cell. Using a fluid model with shear-rate dependent viscosity, we derive a Darcy’s law whose viscosity depends upon the squared pressure gradient. This yields a natural, nonlinear boundary value problem for the pressure. A model proposed recently by Bonn et al. @Phys. Rev. Lett. 75, 2132 ~1995!# follows from this mo...
متن کاملInfluences of Non-Newtonian Viscosity and Elasticity on Potential Flow Analogy by Hele-Shaw Cell
The validity of potential flow analogy by the Hele-Shaw flow of non-Newtonian fluids is examined through experiments using two shear-thinning elastic polymer solutions for three different flow configurations, i.e. flows around a circular cylinder and a square cylinder and flows through an abruptly converging-diverging channel (slit). Although the polymer solutions are highly shear-thinning and ...
متن کاملAnalysis of Pseudo-Turbulence Flow Induced by Bubble Periodic Formation in Non-Newtonian Fluids
Laser Doppler Velocimetry (LDV) has been employed to determine pseudo-turbulence characteristics of the flow field around bubble train forming in non-Newtonian caboxymethylcellulose (CMC) aqueous solution at low gas flow rate condition. The Reynolds stress and turbulent intensity of the liquid were investigated by means of Reynolds time-averaged method. The experimental results show that ax...
متن کاملAn experimental investigation of rheological characteristics of non- Newtonian nanofluids
Rheological characteristics of Al2O3, CuO and TiO2 nano particles were investigated in oil asthe base fluid at 1 and 2 wt.%. Constitutive relations for non-Newtonian fluid were discussedbased on the power-law model. Measured viscosities of each nanofluid were used to evaluatethe power-law and consistency index. Results indicated that the nanofluid viscosity decreasedby increasing the concentrat...
متن کامل