Prediction of onset of Taylor-Couette instability for shear-thinning fluids

Masuda, Hayato; Horie, Takafumi; Hubacz, Robert; Ohta, Mitsuhiro; Ohmura, Naoto

doi:10.1007/s00397-016-0987-7

Cited by 23 publications

(37 citation statements)

References 49 publications

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“…Similar tendency is observed when free (slip) boundary conditions are used [18][19][20]. Recently Masuda et al [21] suggested to use an average viscosity weighted by the strain-rate squared. They found that the critical Reynolds number defined with this average viscosity is the same as for a Newtonian fluid.…”

Section: I1 Brief Review On Taylor-couette Flow Of Shear-thinning Fsupporting

confidence: 60%

“…It is interesting to note that when the characteristic timeλ of the fluid is larger than the advection time d /R 1 Ω −1 1 , the Carreau model tends towards the power-law modelμ =KΓ (nc−1)/2 with a consistency K =μ 0λ (nc−1)/2 . Examples of the values of the Carreau parameters can be found in the literature, particularly for solutions of xanthan gum, stiff-rode-like polymer [21,34,35].…”

Section: Ii2 Carreau Modelmentioning

confidence: 99%

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Taylor-vortex flow in shear-thinning fluids

et al. 2019

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The present paper deals with the Taylor-Couette flow of shear-thinning fluids. It focuses on the first principles understanding the influence of the viscosity stratification and the nonlinear variation of the effective viscosity µ with the shear rateγ on the flow structure in the Taylor vortex flow regime. A wide gap configuration (η = 0.4) is mainly considered. A weakly nonlinear analysis, using the amplitude expansion method at high order is adopted as a first approach to study nonlinear effects. For the numerical computation, the shear-thinning behavior is described by the Carreau model. The rheological parameters are varied in a wide range. The results indicate that the flow field undergoes a significant change as shear-thinning effects increase. First, vortices are squeezed against the inner wall and the center of the patterns are shifted axially towards the radial outflow boundaries (z = 0, z/λ z = 1). This axial shift leads to increasing concentration of vorticity at these positions. The outflow becomes more stronger than the inflow and the inflow zone, where the vorticity is low, increases accordingly. Nevertheless, the strength of the vortices relative to the velocity of the inner cylinder is weaker. Second, the pseudo-Nusselt number, ratio of the torque to that obtained in the laminar flow, decreases. Third, higher harmonics become more relevant and grow faster with Reynolds number. Finally, the modification of the viscosity field is described.

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Section: I1 Brief Review On Taylor-couette Flow Of Shear-thinning Fsupporting

confidence: 60%

Section: Ii2 Carreau Modelmentioning

confidence: 99%

Taylor-vortex flow in shear-thinning fluids

et al. 2019

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“…In order to define Re eff from η eff , it is necessary to properly estimate the effective shear rate,

\overset{\cdot}{γ}

eff . Masuda et al proposed an empirical correlation equation between the rotational speed of the inner cylinder ( ω ) and the effective shear rate (

\overset{\cdot}{γ}

eff ) as follows:

true {\overset{\cdot}{γ}}_{normaleff} = {77.05 n^{0.32} {(\frac{R_{i}}{R_{o}})}^{2} - 88.73 n^{0.31} (\frac{R_{normali}}{R_{normalo}}) + 26.85 n^{0.21}} ω

…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the simulation code was successfully validated. The velocity distribution without heat transfer was already validated in the previous study .…”

Section: Numerical Simulationmentioning

confidence: 99%

Numerical Simulation of Sterilization Processes for Shear‐Thinning Food in Taylor‐Couette Flow Systems

et al. 2019

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The performance of the Taylor‐Couette flow apparatus as a heat sterilizer is numerically investigated. The destruction of Clostridium botulinum and thiamine (vitamin B1) was selected as model reaction. When Taylor vortices were formed in the annular space, the heat transfer significantly enhanced as compared to the case without vortex flow. As a result, the equivalent lethality calculated from the temperature field increased, which is regarded as a quantum leap. Conversely, the improvement of heat transfer induced destruction of thiamine. These results suggest that there is a trade‐off relationship between the enhancement of heat transfer and the avoidance of thermal destruction of nutritional components. In conclusion, the Taylor‐Couette flow sterilizer has the potential for process intensification in heat sterilization processes.

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“…They confirmed that the reliability of this method was ascertained since the conservation of flow similarity was better than that achieved with the conventional Metzner-Otto method, when scaling up the vessels under the condition that the Re eff calculated with this method is constant. In shear-thinning fluid systems, this method for the estimation of effective viscosity has been applied for other flow systems and verified, e.g., Taylor-Couette flow (Masuda et al, 2015(Masuda et al, , 2017b and Rayleigh-Bénard convection (Parmentier 1978;Jenny et al, 2015). Some researchers have reported that K s depends on not only an impeller type, but also rheological properties of a fluid (e.g., Rieger and Novak, 1973;Šesták et al, 1986;Carreau et al, 1992;Tanguy et al, 1996;Anne-Archard et al, 2006).…”

Section: Design Of Process With Rheologically Complex Uidmentioning

confidence: 99%

Intensification of Mixing Processes with Complex Fluids

Ohmura

Masuda

Wang

2018

J. Chem. Eng. Japan / JCEJ

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The present paper provides an overview of the intensi cation of mixing processes with complex uids. First, mixing processes of rheologically complex uids and their design methodology are discussed. An example of process intensi cation of mixing with rheologically complex uids using a Couette-Taylor ow reactor is introduced. Second, the intensi cation of the mixing of a suspension with high concentration solids and a novel approach for solid-liquid separation using a stirred vessel are discussed. Finally, a perspective of the intensi cation of mixing processes with complex uids is summarized.

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Prediction of onset of Taylor-Couette instability for shear-thinning fluids

Cited by 23 publications

References 49 publications

Taylor-vortex flow in shear-thinning fluids

Taylor-vortex flow in shear-thinning fluids

Numerical Simulation of Sterilization Processes for Shear‐Thinning Food in Taylor‐Couette Flow Systems

Intensification of Mixing Processes with Complex Fluids

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