scholarly journals Influence of Shear-thinning Effect on the Characteristics of Journal Film Bearing

2020 ◽  
Vol 56 (1) ◽  
pp. 100
Author(s):  
PEI Shiyuan ◽  
ZHENG Wenbin ◽  
HONG Jun
Keyword(s):  
Shear Thinning ◽  
Thinning Effect

scholarly journals Numerical Well Test Analysis for Polymer Flooding considering the Non-Newtonian Behavior

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Jia Zhichun ◽  
Li Daolun ◽  
Yang Jinghai ◽  
Xue Zhenggang ◽  
Lu Detang
Keyword(s):  
Transient Response ◽  
Polymer Concentration ◽  
Shear Thinning ◽  
Polymer Flooding ◽  
Oil Field ◽  
Well Test ◽  
Well Test Analysis ◽  
Test Analysis ◽  
Pressure Transient ◽  
Thinning Effect

Well test analysis for polymer flooding is different from traditional well test analysis because of the non-Newtonian properties of underground flow and other mechanisms involved in polymer flooding. Few of the present works have proposed a numerical approach of pressure transient analysis which fully considers the non-Newtonian effect of real polymer solution and interprets the polymer rheology from details of pressure transient response. In this study, a two-phase four-component fully implicit numerical model incorporating shear thinning effect for polymer flooding based on PEBI (Perpendicular Bisection) grid is developed to study transient pressure responses in polymer flooding reservoirs. Parametric studies are conducted to quantify the effect of shear thinning and polymer concentration on the pressure transient response. Results show that shear thinning effect leads to obvious and characteristic nonsmoothness on pressure derivative curves, and the oscillation amplitude of the shear-thinning-induced nonsmoothness is related to the viscosity change decided by shear thinning effect and polymer concentration. Practical applications are carried out with shut-in data obtained in Daqing oil field, which validates our findings. The proposed method and the findings in this paper show significant importance for well test analysis for polymer flooding and the determination of the polymer in situ rheology.

scholarly journals Shear-Thinning Effect of the Spinning Disc Mixer on Starch Nanoparticle Precipitation

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1622
Author(s):  
Sahr Sana ◽  
Vladimir Zivkovic ◽  
Kamelia Boodhoo
Keyword(s):  
Shear Rate ◽  
Shear Thinning ◽  
Solute Concentration ◽  
Liquid Films ◽  
High Shear ◽  
Shear Rates ◽  
Disc Surface ◽  
Particle Characteristics ◽  
Thinning Effect ◽  
Spinning Disc

Spinning disc technology is capable of achieving intensified micromixing within thin liquid films created through large shear rates, typically of the order of 103 s−1, generated by means of fast disc surface rotation. In this study the effect of the high shear on solvent–antisolvent mixing and starch nanoparticle precipitation is reported. Rheological studies of starch solutions at 2% w/v and 4% w/v have demonstrated their shear-thinning behaviour at the large shear rates experienced on the spinning disc surface. The effect of such high shear rate on starch nanoparticle precipitation is investigated alongside solute concentration and several other operating parameters such as flow rate, disc rotational speed, and solvent/antisolvent ratio. A reduction in nanoparticle size has been observed with an increase in starch concentration, although agglomeration was found to be more prevalent amongst these smaller particles particularly at larger flow rates and disc rotational speeds. Micromixing time, estimated on the basis of an engulfment mechanism, has been correlated against shear rate. With fast micromixing of the order of 1 ms observed at higher shear rates, and which are practically unaffected by the starch concentrations used, micromixing is not thought to be influential in determining the particle characteristics highlighted in this work.

Analysis of Non-Newtonian Effects in Dynamically Loaded Finite Journal Bearings Including Mass Conserving Cavitation

1992 ◽  
Vol 114 (4) ◽  
pp. 736-744 ◽  
Author(s):  
R. S. Paranjpe
Keyword(s):  
Reynolds Equation ◽  
Relaxation Times ◽  
Shear Thinning ◽  
Limited Range ◽  
Engine Oils ◽  
Dynamically Loaded ◽  
Viscoelastic Effects ◽  
Oil Flow ◽  
Thinning Effect ◽  
Generalized Reynolds Equation

Non-Newtonian effects of multigrade engine oils in dynamically loaded crankshaft bearings are analyzed. The main focus of this work is on the shear-thinning effect. Viscoelastic effects are also considered over a limited range of the relaxation time. It has been shown that the same generalized Reynolds equation used in the Thermohydrodynamic (THD) analysis can be used for analyzing the shear-thinning effects as well. Consequently the shear thinning effect and the THD effect can be treated together. A mass conserving cavitation algorithm developed earlier for doing the THD analysis is used to solve the generalized Reynolds equation. Non-Newtonian shear-thinning significantly affects the power loss, film thickness, and oil flow of a multigrade oil as compared with a Newtonian oil. Over the range of relaxation times considered, no viscoelastic effects were discernible for crankshaft bearings lubricated with multigrade oils.

scholarly journals Characterisation of Hyaluronic Acid Blends Modified by Poly(N-Vinylpyrrolidone)

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5233
Author(s):  
Katarzyna Lewandowska ◽  
Marta Szulc
Keyword(s):  
Hyaluronic Acid ◽  
Shear Thinning ◽  
Tensile Tests ◽  
Infrared Analysis ◽  
Shear Tests ◽  
Casting Method ◽  
Pronounced Increase ◽  
Blend Films ◽  
Solution Casting Method ◽  
Thinning Effect

The viscosity behaviour and physical properties of blends containing hyaluronic acid (HA) and poly(N-vinylpyrrolidone) (PVP) were studied by the viscometric technique, steady shear tests, tensile tests and infrared spectroscopy. Viscometric and rheological measurements were carried out using blends of HA/PVP with different HA weight fractions (0, 0.2, 0.5, 0.8 and 1). The polymer films and HA/PVP blend films were prepared using the solution casting method. The study of HA blends by viscometry showed that HA/PVP was miscible with the exception of the blend with high HA content. HA and its blends showed a shear-thinning flow behaviour. The non-Newtonian indices (n) of HA/PVP blends were calculated by the Ostwald–de Waele equation, indicating a shear-thinning effect in which pseudoplasticity increased with increasing HA contents. Mechanical properties, such as tensile strength and elongation at the break, were higher for HA/PVP films with wHA = 0.5 compared to those with higher HA contents. The elongation at the break of HA/PVP blend films displayed a pronounced increase compared to HA films. Moreover, infrared analysis confirmed the existence of interactions between HA and PVP. The blending of HA with PVP generated films with elasticity and better properties than homopolymer films.

scholarly journals Bubble formation in shear-thinning fluids: Laser image measurement and a novel correlation for detached volume

2017 ◽  
Vol 23 (3) ◽  
pp. 301-309
Author(s):  
Wenyuan Fan ◽  
Xiaohong Yin
Keyword(s):  
Mass Concentration ◽  
Bubble Formation ◽  
Shear Thinning ◽  
Orifice Diameter ◽  
Image System ◽  
Bubble Detachment ◽  
Chamber Volume ◽  
Shear Thinning Fluids ◽  
Gas Chamber ◽  
Thinning Effect

A laser image system has been established to quantify the characteristics of growing bubbles in quiescent shear-thinning fluids. Bubble formation mechanism was investigated by comparing the evolutions of bubble instantaneous shape, volume and surface area in two shear-thinning liquids with those in Newtonian liquid. The effects of solution mass concentration, gas chamber volume and orifice diameter on bubble detachment volume are discussed. By dimensional analysis, a single bubble volume detached within a moderate gas flowrate range was developed as a function of Reynolds number ,Re, Weber number, We, and gas chamber number, Vc, based on the orifice diameter. The results reveal that the generated bubble presents a slim shape due to the shear-thinning effect of the fluid. Bubble detachment volume increases with the solution mass concentration, gas chamber volume and orifice diameter. The results predicted by the present correlation agree better with the experimental data than the previous ones within the range of this paper.

Numerical study on the interaction of transversely oriented ridges in thermal elastohydrodynamic lubrication point contacts using the Eyring shear-thinning model

2016 ◽  
Vol 231 (1) ◽  
pp. 93-106 ◽  
Author(s):  
Jinlei Cui ◽  
Peiran Yang ◽  
Motohiro Kaneta ◽  
Ivan Krupka
Keyword(s):  
Friction Coefficient ◽  
Numerical Study ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Shear Thinning ◽  
Solid Surfaces ◽  
Point Contacts ◽  
Transient Behaviour ◽  
Contact Surfaces ◽  
Thinning Effect

Transient behaviour of tribo-characteristics caused by transversely oriented ridges on point contact surfaces was investigated based on a thermal elastohydrodynamic lubrication analysis. The ridges were assumed to exist on both the contact surfaces with different velocities. Results show that the interaction of ridges gives a large influence on the local film thickness, pressure, friction coefficient, temperatures on both the solid surfaces and temperature in the oil film. It is also pointed out that the size of the contact bodies brings strong effect on the temperature distribution and shear rate as well as on the friction coefficient. Furthermore, it is revealed that under rolling-sliding conditions, the shear-thinning property of the lubricant is negligible when the size of the contact body is large enough. However, shear-thinning effect plays an important role when the size is extremely small.

scholarly journals Non-modal instability in plane Couette flow of a power-law fluid

2011 ◽  
Vol 676 ◽  
pp. 145-171 ◽  
Author(s):  
R. LIU ◽  
Q. S. LIU
Keyword(s):  
Couette Flow ◽  
Power Law ◽  
Energy Method ◽  
Stability Theory ◽  
Initial Conditions ◽  
Shear Thinning ◽  
Plane Couette Flow ◽  
Power Law Fluid ◽  
The Stability ◽  
Thinning Effect

In this paper, we study the linear stability of a plane Couette flow of a power-law fluid. The influence of shear-thinning effect on the stability is investigated using the classical eigenvalue analysis, the energy method and the non-modal stability theory. For the plane Couette flow, there is no stratification of viscosity. Thus, for the stability problem the stress tensor is anisotropic aligned with the strain rate perturbation. The results of the eigenvalue analysis and the energy method show that the shear-thinning effect is destabilizing. We focus on the effect of non-Newtonian viscosity on the transition from laminar flow towards turbulence in the framework of non-modal stability theory. Response to external excitations and initial conditions has been studied by examining the ε-pseudospectrum and the transient energy growth. For both Newtonian and non-Newtonian fluids, it is found that there can be a rather large transient growth even though the linear operator of the Couette flow has no unstable eigenvalue. The results show that shear-thinning significantly increases the amplitude of response to external excitations and initial conditions.

Study of the Shear-Thinning Effect between Polymer Nanoparticle Surfaces during Shear-Induced Aggregation

2021 ◽  
Author(s):  
José Francisco Wilson ◽  
Boleslav Zahradník ◽  
Ondřej Šrom ◽  
Baptiste Jaquet ◽  
Fatima Hassouna ◽  
...  
Keyword(s):  
Shear Thinning ◽  
Polymer Nanoparticle ◽  
Induced Aggregation ◽  
Thinning Effect
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