Non‐Newtonian Flows in Annuli with Variable Eccentric Motion of the Inner Tube

Neto, José Luiz Vieira; Martins, André Leibsohn; Ataíde, Carlos Henrique; Barrozo, M. A. S.

doi:10.1002/ceat.201200239

Cited by 11 publications

(5 citation statements)

References 21 publications

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“…Vieira Neto et al studied the fluid dynamics of non‐Newtonian fluids in an annular space with variable eccentric movement of the inner tube. The effects of four operational variables on the pressure drop were quantified: XG concentration (0.5, 1, and 1.5 mg/g), eccentricity (0, 0.23, and 0.46), inner tube rotation (100 and 200 rpm), and fluid flow rate (5, 7, and 9 m 3 /h).…”

Section: Introductionmentioning

confidence: 99%

Fluid dynamics study of the flow and pressure drop analysis of a non‐Newtonian fluid through annular ducts with unusual cross‐sections

et al. 2016

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This paper concerns an experimental and computational study of the laminar flow developed by a pseudoplastic fluid through a partially-obstructed annulus, considering the effects of eccentricity and inner cylinder rotation. For the eccentric cases the eccentric rotation of the inner tube is applied, which is a novelty in the literature. Pressure drop experimental data are reported for flows of 3 and 9 m 3 /h of a 1 mg/g xanthan gum aqueous solution through a concentric and a 46 % eccentric annulus with partial obstruction of 6 mm, for cases with and without rotation of the inner cylinder (0 and 400 rpm). Numerical simulations were performed using computational fluid dynamics (CFD) techniques which allowed for reporting of axial velocity profiles, apparent viscosity distribution, and pressure drops for a range of eccentricity values (0, 23, and 46 %) and obstruction heights (0, 6, and 12 mm), which were systematically compared for cases with and without rotation of the inner tube (0 and 400 rpm). Comparisons between numerical calculations and the flow data indicated, in general, very close agreement. Eccentric rotation of the inner cylinder presented a distortion effect on the axial velocity and apparent viscosity profiles for the high eccentricity case (46 %) with high obstruction (12 mm), where two maxima regions were observed, one of them near the inner cylinder.

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Section: Introductionmentioning

confidence: 99%

Fluid dynamics study of the flow and pressure drop analysis of a non‐Newtonian fluid through annular ducts with unusual cross‐sections

et al. 2016

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“…The parameters K, A, B, C , and D of these equations were estimated by a regression technique , using the experimental results obtained with the OTH. Tab.…”

Section: Resultsmentioning

confidence: 99%

Effects of Solids Concentration and Underflow Diameter on the Performance of a Newly Designed Hydrocyclone

2017

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Solid‐liquid and liquid‐liquid separations in a hydrocyclone are versatile and require low maintenance costs. The demand for process improvement and cost reduction has motivated numerous optimization studies. The performance of a newly designed hydrocyclone is evaluated. The proposed device was obtained by application of differential evolution techniques and is called optimized thickening hydrocyclone (OTH). The OTH provides promising results, leading simultaneously to low Euler numbers and high solids concentrations of the underflow streams. Compared to the conventional Rietema hydrocyclone, it shows higher efficiency and better thickening power. The effects of solids concentration and underflow diameter on the performance of the OTH are quantified and a design equation for this device is proposed.

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“…As shown in Figure 4 and Figure 5, the mixture of carrageenan with amino acids leads to interesting results, mainly the formation of a gel when mixing carrageenan with lysine, and the break of the viscous state of carrageenan when mixing with arginine or serine. Viscosity is directly associated with molecular interactions; the greater the intermolecular forces, the higher the viscosity of the system [77]. Several natural systems are formed and structured by electrostatic complexes between proteins and polysaccharides.…”

Section: Discussionmentioning

confidence: 99%

“…The nature of the electrically charged group also influences the strength of interactions. Certain proteins interact more strongly with polysaccharides containing sulfonic groups than polysaccharides with only carboxylic groups [77]. Most proteins have some lysine residues; the amino groups of lysine are usually exposed on the protein's surface and are highly reactive when protonated.…”

Section: Discussionmentioning

confidence: 99%

“…The high reactivity of carrageenan with lysine is due to the strong electrostatic interaction between the negatively charged groups of carrageenan and the positively charged side chain of lysine. Interactions between carrageenan and lysine can be observed by the gelation of the solution [77]. Arginine has a guanidine group and an end terminal amine group, which carries a positive charge under physiological conditions because of their intrinsic pKa; although the guanidine group is protonated, its positive charge is delocalized due to the presence of the conjugated double bonds between carbon and nitrogen atoms [68].…”

Section: Discussionmentioning

confidence: 99%

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Carrageenan-amino acid interaction as a tool for understanding atherosclerotic process initiation

Chiconi de Picoli,

Araújo Soares,

Marques Gonçalves

et al. 2024

ELECTRON J GEN MED

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Atherosclerosis is the primary trigger for severe pathologies. The atherosclerotic inflammatory process is well known after low-density lipoprotein (LDL) adhesion in blood vessel walls, however, limited information exists regarding LDL penetration into subendothelial layers. Here, we propose for the first time, to the best of our knowledge, the pathway for the initial trajectory of the lipid molecules internalization into the arterial endothelial tissue. The investigation shows a computational model analyzing molecules involved in the atherosclerotic process, specifically LDL and molecules of the vascular endothelium. The theoretical model was experimentally tested using carrageenan to simulate the anionic counterparts of vascular tissue and amino acids from apolipoprotein B-100. The molecular interactions were analyzed by conductimetric titration, FTIR, and rheology. The computational model identified potential amino acids involved in the process, and the experimental results demonstrated the interaction between lysine and polymer, as the mechanism of adhesion, confirming the model.

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Non‐Newtonian Flows in Annuli with Variable Eccentric Motion of the Inner Tube

Cited by 11 publications

References 21 publications

Fluid dynamics study of the flow and pressure drop analysis of a non‐Newtonian fluid through annular ducts with unusual cross‐sections

Fluid dynamics study of the flow and pressure drop analysis of a non‐Newtonian fluid through annular ducts with unusual cross‐sections

Effects of Solids Concentration and Underflow Diameter on the Performance of a Newly Designed Hydrocyclone

Carrageenan-amino acid interaction as a tool for understanding atherosclerotic process initiation

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