Experimental investigation on convective heat transfer of Shear-thinning fluids by elastic turbulence in a serpentine channel

Yang, Haie; Yao, Guice; Wen, Dongsheng

doi:10.1016/j.expthermflusci.2019.109997

Cited by 18 publications

(9 citation statements)

References 51 publications

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“…This is because of the increase in the pressure loss due to the increase in the elastic stresses at this micelle breakage rate, which ultimately leads to the emergence of elastic instability. This sudden rise of the pressure drop has also been seen in flows of viscoelastic fluids for other geometries, like the flow past an obstacle 64,65 or the flow through a serpentine microchannel 66,67 wherein the elastic instability and elastic turbulence phenomena have been observed.…”

Section: Resultsmentioning

confidence: 60%

Flow dynamics of wormlike micellar solutions through a model porous media

Khan¹,

Sasmal²

2021

Preprint

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The flow of viscoelastic wormlike micellar solutions (WLMs) in porous media is encountered in many practical applications like enhanced oil recovery or groundwater remediation. To understand the flow dynamics of these complex fluids in porous media, a model porous media consisting of a straight microchannel with micropore throats present in it, is very often used. In this study, we perform an extensive numerical investigation to understand the flow dynamics of wormlike micellar solutions based on the two-species Vasquez-Cook-McKinley (VCM) model for micelles through such model porous media. We find the existence of an elastic instability once the Weissenberg number exceeds a critical value; likewise, it was seen in many prior experimental and numerical studies dealing with polymer solutions. However, for the present case of a WLM solution, we observe that this elastic instability is greatly influenced by the breakage and reformation mechanisms of the wormlike micelles. In particular, we notice that the intensity of this instability (characterized by the fluctuating flow fields) increases as the Weissenberg number increases; however, beyond a critical value of it, this elastic instability and/or the flow field fluctuation is suppressed because of the breakage of long micelles. This is in contrast to the polymer solutions for which the flow field gradually transits to a more chaotic and turbulent-like state (or the so-called elastic turbulence state) as the Weissenberg number gradually increases. Additionally, we observe that the flow dynamics of these WLM solutions are strongly dependent on the type of micropore throat, the number of pore throats, and the spacing between two consecutive pore throats. An extensive discussion on the pressure drop and apparent viscosity is also presented in the present study. Although this study is carried out for a model porous media; however, we hope it will facilitate a better understanding of the flow behaviour of wormlike micellar solutions in an actual more complex porous media.

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Section: Resultsmentioning

confidence: 60%

Flow dynamics of wormlike micellar solutions through a model porous media

Khan¹,

Sasmal²

2021

Preprint

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“…One of the methods to investigate their flow-based property is to determine the shear rate and shear stress of the flow in the fluids. The water-based nanofluids generally behave as shear-thinning fluids at temperatures ranging from 30 to 80 °C [ 64 ]. Over the past few decades numerous scholars have studied flow properties.…”

Section: Resultsmentioning

confidence: 99%

Investigation on Rheological Properties of Water-Based Novel Ternary Hybrid Nanofluids Using Experimental and Taguchi Method

et al. 2021

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This study presents the rheological behavior of water-based GO-TiO2-Ag and rGO-TiO2-Ag ternary-hybrid nanofluids. The impact of nanoparticles’ volumetric concentration and temperature on the rheological properties were studied. All experiments were performed under temperatures ranging from 25 to 50 °C in the solid volume concentration range of 0.5–0.00005%. The data optimization technique was adopted using the Taguchi method. The types of nanomaterials, concentration, temperature, and shear rate were chosen to optimize the viscosity and shear stress. The effect of shear stress, angular sweep, frequency sweep, and damping factor ratio is plotted. The experimental results demonstrated that the rheological properties of the ternary hybrid nanofluid depend on the ternary hybrid nanofluid’s temperature. The viscosity of ternary hybrid nanofluids (THNf) change by 40% for GO-TiO2-Ag and 33% for rGO-TiO2-Ag when temperature and shear rates are increased. All the ternary hybrid nanofluids demonstrated non-Newtonian behavior at lower concentrations and higher shear stress, suggesting a potential influence of nanoparticle aggregation on the viscosity. The dynamic viscosity of ternary hybrid nanofluid increased with enhancing solid particles’ volume concentration and temperature.

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“…Even within these published studies there are still some inconsistent results. For example, the heat transfer enhancement against Wi increases with increasing polymer concentration in Refs [34,43], which contradicts to the observation of Li et al [36]. Indeed, polymer rheology being sensitive with many other factors that could affect the heat transfer performance has not received attention so far [34,44].…”

Section: Introductionmentioning

confidence: 84%