Numerical and Experimental Investigation of a Non-Newtonian Flow in a Collapsed Elastic Tube

Tanner, Franz X.; Feigl, Kathleen; Nahar, Samsun; Jeelani, Shaik; Case, W. R.; Windhab, Erich J.

doi:10.3933/applrheol-22-63910

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…In our DIW process, the average shear rate, experienced by the inks inside the DIW nozzle, was calculated to be approximately 37 s −1 using the formula , where n , V ave. , and r are power law index, average flow velocity (3 mm s −1 ), and the nozzle radius (205 µm), respectively [ 40 , 41 ]. The power law index of 0.63 was used to calculate the average shear rate.…”

Section: Methodsmentioning

confidence: 99%

Engineering Nano/Microscale Chiral Self-Assembly in 3D Printed Constructs

Esmaeili,

Akbari,

George

et al. 2023

Nano-Micro Lett.

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Helical hierarchy found in biomolecules like cellulose, chitin, and collagen underpins the remarkable mechanical strength and vibrant colors observed in living organisms. This study advances the integration of helical/chiral assembly and 3D printing technology, providing precise spatial control over chiral nano/microstructures of rod-shaped colloidal nanoparticles in intricate geometries. We designed reactive chiral inks based on cellulose nanocrystal (CNC) suspensions and acrylamide monomers, enabling the chiral assembly at nano/microscale, beyond the resolution seen in printed materials. We employed a range of complementary techniques including Orthogonal Superposition rheometry and in situ rheo-optic measurements under steady shear rate conditions. These techniques help us to understand the nature of the nonlinear flow behavior of the chiral inks, and directly probe the flow-induced microstructural dynamics and phase transitions at constant shear rates, as well as their post-flow relaxation. Furthermore, we analyzed the photo-curing process to identify key parameters affecting gelation kinetics and structural integrity of the printed object within the supporting bath. These insights into the interplay between the chiral inks self-assembly dynamics, 3D printing flow kinematics and photo-polymerization kinetics provide a roadmap to direct the out-of-equilibrium arrangement of CNC particles in the 3D printed filaments, ranging from uniform nematic to 3D concentric chiral structures with controlled pitch length, as well as random orientation of chiral domains. Our biomimetic approach can pave the way for the creation of materials with superior mechanical properties or programable photonic responses that arise from 3D nano/microstructure and can be translated into larger scale 3D printed designs.

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Section: Methodsmentioning

confidence: 99%

Engineering Nano/Microscale Chiral Self-Assembly in 3D Printed Constructs

Esmaeili,

Akbari,

George

et al. 2023

Nano-Micro Lett.

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Influence of flowing fluid property through an elastic tube on various deformations along the tube length

2019

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The study of fluid flow characteristics in collapsible elastic tubes is useful to understand biofluid mechanics encountered in the human body. The research work presented here is aimed at thoroughly investigating the influence of both Newtonian and/or non-Newtonian fluids (low and high shear thinning) during steady flow through an elastic tube on various tube deformations, which enables understanding of the interaction between wall motion, fluid flow, and intestinal transmembrane mass transfer as a crucial contribution to a mechanistic understanding of bioaccessibility/bioavailability. It is observed that for a given steady volume flow rate, the tube is buckled from an elliptical shape to a line or area contacted two lobes as the critical external pressure is increased. The downstream transmural pressure is found to get more negative than that at the upstream as the outlet pressure decreased due to stronger tube collapse resulting in a reduced cross-sectional area. The experimental results depict that the tube cross-sectional area decreased by only about a factor of one for PEG (polyethylene glycol) and about a factor of six for both CMC (carboxymethyl cellulose) and PAA (polyacrylamide) from the undeformed one under an applied external pressure of 105 mbar. The corresponding maximum velocity increased by a factor of two during steady flow of shear-thinning fluids. The shear-thinning behavior of both CMC and PAA solutions is clearly observed at a constant flow rate of 17 ml/s as the tube cross-sectional area decreased due to an increase in compressive transmural pressure. In addition, the viscosity of PAA is drastically decreased due to its high shear-thinning behavior than that of the CMC under the same applied external pressure.

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Simulations of Newtonian and Non-Newtonian Flows in Deformable Tubes

Al-Habahbeh

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Numerical and Experimental Investigation of a Non-Newtonian Flow in a Collapsed Elastic Tube

Cited by 3 publications

References 8 publications

Engineering Nano/Microscale Chiral Self-Assembly in 3D Printed Constructs

Engineering Nano/Microscale Chiral Self-Assembly in 3D Printed Constructs

Influence of flowing fluid property through an elastic tube on various deformations along the tube length

Simulations of Newtonian and Non-Newtonian Flows in Deformable Tubes

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