KINETIC RESEARCH OF CROSSLINKING OF POLYETHYLENE FOR ROTARY AND ROTORLESS CURE METERS AND A ROTATIONAL VISCOMETER OF THE “PLANE–PLANE” SYSTEM

2019 ◽  
Vol 5 ◽  
pp. 53-62
Author(s):  
I. N. PYATIN ◽  
◽  
L. V. ARSENYEVA ◽  
R. YU. BELKIN ◽  
YU. V. KURBATOVA ◽  
...  
2021 ◽  
Vol 59 (3) ◽  
pp. 62-68
Author(s):  
Deyun Li ◽  
Hongqiang Fang ◽  
Xu Zhang ◽  
Jin Qi ◽  
Zuqing Zhu

1982 ◽  
Vol 14 (6-7) ◽  
pp. 475-489 ◽  
Author(s):  
H W Campbell ◽  
P J Crescuolo

Rheological measurements were conducted on a variety of anaerobically digested sewage sludges to evaluate the potential use of rheology in describing the effects of chemical conditioning on the physical characteristics of sludges. The objectives of the study were to evaluate the influence of the method of chemical conditioning on rheological measurements; to determine the response of the viscometer system to changes in the instrument variables; and to evaluate interrelationships between rheology and other physical properties. All rheological measurements were made using a coaxial rotational viscometer. Evaluation of a variety of test procedures identified that both the method of adding chemical conditioners, and the acceleration rate of the rotational viscometer, could significantly alter the shape of the rheograms. A suggested methodology was identified and selected samples were analyzed in triplicate to test the reproducibility of the procedures. Existing mathematical models do not adequately describe the variety of flow behaviour patterns observed with sewage sludge. The concepts of yield stress and apparent viscosity also have limited value due to problems of definition and calculation. A parameter termed the “instantaneous viscosity”, defined as the derivative of the flow curve, is suggested as being more suitable for describing sludge behaviour. The relationships between chemical conditioning, particle size distribution and applied shear were explored. As polymer addition increased, the sludge particles became more susceptible to shear breakup. The extent of particle size reduction was a function of the rate of shear and the time during which the shear was maintained.


Author(s):  
Adam Lipchitz ◽  
Theophile Imbert ◽  
Glenn D. Harvel

The density and viscosity Field’s metal is measured in this work and compared to traditional liquid metal coolants such as sodium and lead-bismuth eutectic. Field’s metal is a eutectic of the ternary In-Bi-Sn system. The alloy is by weight percent is 51% indium, 32.5% bismuth and 16.5% tin and possesses a melting temperature of 333 K. This work experimentally measures the density and viscosity of Field’s metal for numerical modeling and thermal hydraulic applications. The density of Field’s metal is measured using a pycnometer. The density is determined for both its solid and liquid states. In its liquid state Field’s metal is found to have a linear dependence with respect to increasing temperature. The viscosity of Field’s metal is measured using a rotational viscometer. The viscosity is measured is to be 27 mPa-s at 353 K, however further investigation is required to determine a trend at higher temperatures.


Author(s):  
D Sagdeev ◽  
◽  
Ch. Isyanov ◽  
I Gabitov ◽  
V Khairutdinov ◽  
...  

The density and dynamic viscosity of four light, medium, and heavy (extra-viscous) crude oil samples from Tatarstan Oil Field (Russian Federation) have been measured over the temperature range from (293 to 473) K (for density) and from (293 to 348) K (for viscosity) at atmospheric pressure (101 kPa). The density measurements were made using a new densimeter based on hydrostatic weighing method. The viscosity measurements of the same crude oil samples were made us-ing Brookfield rotational viscometer (DV-II+PRO, LVD-II+PRO). The combined expanded uncertainty of the density, viscosity, atmospheric pressure, and temperature measurements at 0.95 confidence level with a coverage factor of k = 2 is estimated to be 0.16 %, 1.0 %, 1.0 %, and 20 mK, respectively. For validation of the reliability and accuracy of the measured density data and correct operation of the new densimeter, all oil samples were measured using the pycnometric method. The present study showed that the densities measured using the new hydrostatic weighing densimeter (HWD) are agree with the values obtained with pycnometric method within (0.03 to 0.14) %. The measured density and viscosity data were used to develop widerange correlations as a function of temperature and API characteristics. The measured densities were represented using simple function of temperature (polynomial type) with API gravity dependent parameters with an accuracy of AAD within from (0.10 to 0.18) %. The measured viscosity data were also used to develop linear Arrhenius and VTF models. API gravity dependence of the Arrhenius parameters was studied.


2021 ◽  
Author(s):  
Chen Hongbo ◽  
Okesanya Temi ◽  
Kuru Ergun ◽  
Heath Garett ◽  
Hadley Dylan

Abstract Recent studies highlight the significant role of drilling fluid elasticity in particle suspension and hole cleaning during drilling operations. Traditional methods to quantify fluid elasticity require the use of advanced rheometers not suitable for field application. The main objectives of the study were to develop a generalized model for determining viscoelasticity of a drilling fluid using standard field-testing equipment, investigate the factors influencing drilling fluid viscoelasticity in the field, and provide an understanding of the viscoelasticity concept. Over 80 fluid formulations used in this study included field samples of oil-based drilling fluids as well as laboratory samples formulated with bentonite and other polymers such as partially-hydrolyzed polyacrylamide, synthesized xanthan gum, and polyacrylic acid. Detailed rheological characterizations of these fluids used a funnel viscometer and a rotational viscometer. Elastic properties of the drilling fluids (quantified in terms of the energy required to cause an irreversible deformation in the fluid's structure) were obtained from oscillatory tests conducted using a cone-and-plate type rheometer. Using an empirical approach, a non-iterative model for quantifying elasticity correlated test results from a funnel viscometer and a rotational viscometer. The generalized model was able to predict the elasticity of drilling fluids with a mean absolute error of 5.75%. In addition, the model offers practical versatility by requiring only standard drilling fluid testing equipment to predict viscoelasticity. Experimental results showed that non-aqueous fluid (NAF) viscoelasticity is inversely proportional to the oil-water ratio and the presence of clay greatly debilitates the elasticity of the samples while enhancing their viscosity. The work efforts present a model for estimating drilling fluid elasticity using standard drilling fluid field-testing equipment. Furthermore, a revised approach helps to describe the viscoelastic property of a fluid that involves quantifying the amount of energy required to irreversibly deform a unit volume of viscoelastic fluid. The methodology, combined with the explanation of the viscoelasticity concept, provides a practical tool for optimizing drilling operations based on the viscoelasticity of drilling fluids.


Author(s):  
Lyudmila P. SEMIKHINA ◽  
Daniil D. Korovin

A Brookfield DV-II + Pro rotational viscometer was used to study the viscosity of 7 samples of concentrated nanodispersed systems (nanofluids) with a similar viscosity (6-22 mPa ∙ s), the particles of the dispersed phase in which are nanosized surfactant micelles and conglomerates from them. It was found that for 5 out of 7 studied reagents, there is a decrease in viscosity typical for dispersed systems with an increase in the shear rate, and their flow curves, that is, the dependence of the shear stress on the shear rate, correspond to the ideal plastic flow of non-Newtonian fluids. Moreover, with high reliability, R2 ≥ 0.999 is described by the Bingham equation with a small value of the limiting shear stress (less than 0.2 Pa). It is shown that all the studied reagents are also characterized by an increase in the activation energy of a viscous flow Е with an increase in the shear rate. As a result, a decrease in viscosity with an increase in shear rate, typical for disperse systems, including nanofluids, is provided by a more significant increase in entropy changes ΔS compared to Е. It has been substantiated that, depending on the ratio between the activation energy of viscous flow Е and the change in entropy ΔS, the viscosity of concentrated micellar dispersed systems with an increase in the shear rate can decrease, remain unchanged, and increase. The last two cases, not typical for disperse systems and nanofluids, were identified and studied using the example of two demulsifiers, RIK-1 and RIK-2, with a maximum of a very narrow particle size distribution at 160 ± 5 nm, corresponding to the size of a special type of very stable micelles Surfactant — vesicle.


Author(s):  
Shinya NAKASHITA ◽  
Kyeongmin KIM ◽  
Yuki IMAMURA ◽  
Tadashi HIBINO

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