Comparative Response of Newtonian and Non-Newtonian Fluids Subjected to Exothermic Reactions in Shear Flow

Chinyoka, T.

doi:10.1007/s40819-021-01023-4

Cited by 17 publications

(23 citation statements)

References 18 publications

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“…The current study builds on the investigations in [1][2][3] and extends these investigations to free-surface, gravity-driven, thin-film flows with convective heat exchange at the free-surface. Additionally and alternatively, the current work extends the combined (particle-free) fluid-dynamics studies in [25] and [29] to the inclusion of solid nanoparticles and hence raising the cited works to nanofluid-dynamics.…”

mentioning

confidence: 85%

“…Noting the fundamental importance of the rheology of the base fluid to the modern applications of nanofluids, the studies, say in [1][2][3] focus attention on non-Newtonian (specifically polymeric) base-fluids under various flow conditions. The widespread importance of non-Newtonian fluids, both the Generalized Newtonian Fluids (GNF) as well as the polymeric (viscoelastic) fluids, in contemporary application is quite straightforward for example [1][2][3]6,8,[25][26][27][28][29][30][31][32][33][34].…”

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confidence: 99%

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Computational-Analysis of the Non-Isothermal Dynamics of the Gravity-Driven Flow of Viscoelastic-Fluid-Based Nanofluids Down an Inclined Plane

Khan¹,

Chinyoka²,

Gill³

2023

Fluid Dynamics &Amp; Materials Processing

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The paper explores the gravity-driven flow of the thin film of a viscoelastic-fluid-based nanofluids (VFBN) along an inclined plane under non-isothermal conditions and subjected to convective cooling at the free-surface. The Newton's law of cooling is used to model the convective heat-exchange with the ambient at the free-surface. The Giesekus viscoelastic constitutive model, with appropriate modifications to account for non-isothermal effects, is employed to describe the polymeric effects. The unsteady and coupled non-linear partial differential equations (PDEs) describing the model problem are obtained and solved via efficient semi-implicit numerical schemes based on finite difference methods (FDM) implemented in Matlab. The response of the VFBN velocity, temperature, thermal-conductivity and polymeric-stresses to variations in the volume-fraction of embedded nanoparticles is investigated. It is shown that these quantities all increase as the nanoparticle volume-fraction becomes higher. KEYWORDSSemi-implicit numerical scheme; finite difference methods; viscoelastic-fluid-based nanofluid (VFBN); nonisothermal viscoelastic flow; giesekus constitutive model; nanofluid thermal-conductivity; gravity-driven flow Nomenclature Variables and ConstantsÃ

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confidence: 85%

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confidence: 99%

Computational-Analysis of the Non-Isothermal Dynamics of the Gravity-Driven Flow of Viscoelastic-Fluid-Based Nanofluids Down an Inclined Plane

Khan¹,

Chinyoka²,

Gill³

2023

Fluid Dynamics &Amp; Materials Processing

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“…Although non-Newtonian fluids have a long history, few related applications have been reported 1 . Furthermore, non-Newtonian fluids are acutely sensitive to temperature 10 .…”

Section: Introductionmentioning

confidence: 99%

Non-reciprocal and Non-Newtonian Mechanical Metamaterials

Wang

Martínez

Ulliac

et al. 2023

Preprint

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Non-Newtonian liquids are characterized by a stress and velocity-dependent dynamical response. In elasticity, and in particular in the field of phononics, reciprocity in the equations acts against obtaining a directional response for passive media. Active stimuli-responsive materials have been conceived to overcome it. Significantly, Milton and Willis have shown theoretically in 2007 that quasi-rigid bodies containing masses at resonance can display a very rich dynamical behavior, hence opening a route toward the design of non-reciprocal and non-Newtonian metamaterials. In this paper, we design a solid structure that displays unidirectional shock resistance, thus going beyond Newton’s second law in analogy to non-Newtonian fluids. We design the mechanical metamaterial with finite element analysis and fabricate it using 3D printing at the centimetric scale (with fused deposition modeling – FDM) and at the micrometric scale (with two-photon lithography – TPL). The non-Newtonian elastic response is measured via dynamical velocity-dependent experiments. Reversing the direction of the impact, we further highlight the intrinsic non-reciprocal response.

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“…There are also external factors such as fluid temperature or standing time between preparation and ingestion that can also affect the therapeutic effect of TPs [ 21 ]. Newtonian fluids do not depend on shear rate (inelastic behavior) but only on temperature [ 14 , 22 ]. They present an indirect effect: Newtonian fluid viscosity decreases with the increment of temperature.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, the multiple dependencies on several variables of non-Newtonian fluids (shear rate, temperature), make them unpredictable and they, therefore, need to be studied individually. Several mathematical approaches have been performed for these fluids, such as the Arrhenius equation [ 22 ], which reflects the behavior of non-Newtonian fluids with temperature [ 23 ]. Finally, we also need to consider the impact X-ray contrast may have on ShV when performing videofluoroscopy (VFS).…”

Section: Introductionmentioning

confidence: 99%

Proposal for a Standard Protocol to Assess the Rheological Behavior of Thickening Products for Oropharyngeal Dysphagia

et al. 2022

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Increasing shear viscosity (ShV) in thickening products (TP) is a valid therapeutic strategy for oropharyngeal dysphagia (OD). However, salivary amylase in the oral phase and shear rate in the pharyngeal phase of swallowing can change the viscosity of TPs when swallowed. This study aims to design and validate a rheological protocol to reproduce the oral and pharyngeal factors that affect the therapeutic effect of TPs and report the viscosity measurements in a standardized scientific and precise manner. We measured (a) the variability of the ShV measurements across several laboratories; (b) the in vitro and ex vivo properties of TPs and (c) the impact of the X-ray contrast Omnipaque, temperature and resting time on the rheological properties of TPs. A common protocol was applied in four international laboratories to assess five ShV values (100, 200, 400, 800 and 1600 mPa·s) for the xanthan-gum TP Tsururinko Quickly (TQ). The protocol included the dose (g/100 mL water), stirring procedure and standing time before measurement. Each value was characterized at the shear rate of 50 and 300 s−1 pre- and post-oral incubation in eight volunteers. The effect of temperature, standing time and Omnipaque was assessed. The main results of the study were: (a) The mean intra-laboratory variability on the ShV at all levels was very low: 0.85%. The mean inter-laboratory variability was higher: 9.3%; (b) The shear thinning of TQ at 300 s−1 was 75–80%. Increasing the temperature or standing time did not affect the ShV, and oral amylase caused a small decrease; (c) Omnipaque slightly decreased the dose of TP and hardly affected the amylase resistance or shear thinning. This study showed that different laboratories can obtain very accurate and similar ShV measurements using this protocol which uses scientific, universal SI units (mPa·s). Our protocol accurately reproduces oral and pharyngeal factors affecting the therapeutic effect of TPs. The addition of X-ray contrast did not produce significant changes.

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Comparative Response of Newtonian and Non-Newtonian Fluids Subjected to Exothermic Reactions in Shear Flow

Cited by 17 publications

References 18 publications

Computational-Analysis of the Non-Isothermal Dynamics of the Gravity-Driven Flow of Viscoelastic-Fluid-Based Nanofluids Down an Inclined Plane

Computational-Analysis of the Non-Isothermal Dynamics of the Gravity-Driven Flow of Viscoelastic-Fluid-Based Nanofluids Down an Inclined Plane

Non-reciprocal and Non-Newtonian Mechanical Metamaterials

Proposal for a Standard Protocol to Assess the Rheological Behavior of Thickening Products for Oropharyngeal Dysphagia

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