scholarly journals Apparent Viscosity Measurement of Solid-liquid Coexisting Fluid by Falling Ball Method for Evaluation Iron Particle Sedimentation Velocity in Slag

2021 ◽  
Vol 61 (12) ◽  
pp. 2915-2922
Author(s):  
Wei Li ◽  
Takayuki Iwama ◽  
Huafang Yu ◽  
Shigeru Ueda ◽  
Noritaka Saito ◽  
...  
Keyword(s):  
Apparent Viscosity ◽  
Iron Particle ◽  
Sedimentation Velocity ◽  
Viscosity Measurement ◽  
Particle Sedimentation ◽  
Solid Liquid

scholarly journals Numerical Simulation of the Influence of Taylor Vortex on the Apparent Viscosity Measurement of Semi-Solid Metallic Based On ANSYS Fluent

2022 ◽  
Vol 2152 (1) ◽  
pp. 012061
Author(s):  
Enjie Dong ◽  
Gan Li ◽  
Xiaogang Hu ◽  
Zhong Li ◽  
Juan Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Apparent Viscosity ◽  
Viscosity Measurement ◽  
Taylor Vortex ◽  
Flow State ◽  
Flow Conditions ◽  
Unstable Flow ◽  
Concentric Cylinder ◽  
Ansys Fluent ◽  
Semi Solid

Abstract The apparent viscosity of semi-solid metallic slurry with a low solid fraction, which is one of the most essential parameters for representing the rheological behavior, is mainly measured by the concentric cylinder rotational approach. The principle of this method is based on the assumptions that the fluid is in an ideal laminar flow state and obey the Newton’s internal friction law. However, as the angular velocity ω increases, the fluid undergoes a transition from a stable laminar flow state to a Taylor vortex and turbulent flow state. These unstable flow conditions such as Taylor vortex and turbulence have a severe impact on the accuracy of apparent viscosity measurement. However, these unstable flow conditions are difficult to monitored and analyzed in real time through experimental methods. Computer numerical simulation technology provides the possibility and convenience for the visualization of the flow state of the semi-solid metallic slurry in the measurement system. In this work, ANSYS Fluent was used to simulate the apparent viscosity measurement process of semi-solid slurry, and the flow state transition process of the semi-solid slurry in the measurement system was successfully visualized and analyzed. In order to avoid the influence of Taylor vortex, combined with the measurement principle of the concentric cylinder rotational rheometer and Taylor’s study on flow stability, the empirical equation of limiting speed to avoid Taylor vortex in the process of Searle rheometer viscosity measurement is given.

Viscosity (Part 1)

1981 ◽  
Vol 14 (3) ◽  
pp. 73-78 ◽  
Author(s):  
D. C-H. Cheng
Keyword(s):  
Apparent Viscosity ◽  
Absolute Measurement ◽  
Viscosity Measurement ◽  
Newtonian Fluids ◽  
Current Work ◽  
Practical Implementation ◽  
Newtonian Viscosity ◽  
Know How ◽  
The Subject ◽  
Newtonian Liquids

This article reviews the standard specifications related to viscosity measurement, issued by ASTM, BSI, IP and other standard bodies, and their applications. The know-how embodied in these specifications is discussed in relation to knowledge recorded in the literature and some aspects of practical implementation and use are considered. It is shown that standards and calibration are well established for Newtonian liquids and viscosity measurement can be accurate and precise. But, for non-Newtonian fluids, the specifications give apparent viscosity, not absolute values; and even then the results, although they can be precise, are of uncertain accuracy. It is pointed out that information exists in the literature on the subject of absolute measurement of non-Newtonian viscosity but that it needs to be simplified and codified before it can be incorporated into standard specifications. Current work towards this end is referred to.

Non-Newtonian numerical modelling of solder paste viscosity measurement

2019 ◽  
Vol 31 (3) ◽  
pp. 176-180 ◽  
Author(s):  
Tareq I. Al-Ma’aiteh ◽  
Oliver Krammer
Keyword(s):  
Apparent Viscosity ◽  
Material Model ◽  
Viscosity Measurement ◽  
Solder Paste ◽  
Material Models ◽  
Stencil Printing ◽  
Content Type ◽  
Shear Rates ◽  
Paste Viscosity ◽  
Measured Viscosity

PurposeThe purpose of this paper is to present the establishment of a computational fluid dynamics model for investigating different non-Newtonian rheological models of solder pastes by simulating solder paste viscosity measurement. A combined material model was established which can follow the measured, apparent viscosity values with lower error.Design/methodology/approachThe model included a parallel plate arrangement of rheometers. The diameter of the plate was 50 mm, whereas the gap between the plates was 0.5 mm. Only one quarter of the plate was modelled to enable using fine enough mesh, while keeping the calculation time low. Non-Newtonian properties were set using user defined function in Ansys, based on the Cross and Carreau–Yasuda material models. The viscosity values predicted by the mathematical models were compared to measured viscosity values of different types of solder pastes.FindingsIt was found that the Cross model predicts the apparent viscosity with a relatively high error (even approximately 50 per cent) at lower shear rates, whereas the Carerau–Yasuda model has higher errors at higher shear rates. The application of the proposed, combined model can result in a much lower error in the apparent viscosity between the calculated and measured viscosity values.Originality/valueThe error of Cross and Carreau–Yasuda material models has not been investigated yet in details. The proposed, combined material model can be applied for subsequent simulations via the described UDF, e.g. in the numerical modelling of the stencil printing. This can result in a more accurate modelling of the stencil printing process, which is inevitable considering the printing of solder paste for today fine-pitch, small size components.

scholarly journals Rheology of the gel formed in the California Mastitis Test

2008 ◽  
Vol 75 (4) ◽  
pp. 385-391 ◽  
Author(s):  
C Johan R Verbeek ◽  
Stephen S Xia ◽  
David Whyte
Keyword(s):  
Somatic Cell ◽  
Apparent Viscosity ◽  
Cell Concentration ◽  
Strong Dependence ◽  
Relative Viscosity ◽  
Viscosity Measurement ◽  
California Mastitis Test ◽  
Rotational Viscometry ◽  
Test Conditions ◽  
Viscosity Increase

The California Mastitis Test has previously been adapted for use in an inline, cow-side sensor and relies on the fact that the viscosity of the gel formed during the test is proportional to the somatic cell concentration. In this paper, the use of capillary and rotational viscometry was compared in light of the expected rheology of the gel formed during the test. It was found that the gel is non-Newtonian, but the initial phase of viscosity increase was not due to shear dependence, but rather due to the gelation reaction. The maximum apparent viscosity of the gel was shear dependent while the time it took to reach the maximum was not truly shear dependent, but was rather dependent on the degree of mixing during gelation. This was confirmed by introducing a delay time prior to viscosity measurement, in both capillary and rotational viscometry. It was found that by mixing the reagent and infected milk, then delaying viscosity measurement for 30 s, shortened the time it took to reach maximum viscosity by more than 60 s. The maximum apparent viscosity, however, was unaffected. It was found that capillary viscometry worked well to correlate relative viscosity with somatic cell count, but that it was sensitive to the reagent concentration. It can therefore be deduced that the rheology of the gel is complicated not only by it being non-Newtonian, but also by the strong dependence on test conditions. These make designing a successful sensor much more challenging.

scholarly journals Combination of Natural and Thermosensitive Polymers in Flocculation of Fine Silica Dispersions

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Angel Licea-Claverie ◽  
Simona Schwarz ◽  
Christine Steinbach ◽  
Sandra Montserrat Ponce-Vargas ◽  
Sabine Genest
Keyword(s):  
Sedimentation Velocity ◽  
Laser Diffraction ◽  
Temperature Sensitive ◽  
Thermosensitive Polymer ◽  
Separation Processes ◽  
Thermosensitive Polymers ◽  
Novel Strategy ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Sensitive Behavior

A novel strategy for faster and better flocculation in solid-liquid separation processes is reported: the use of the natural polyelectrolyte chitosan (CH2500) in combination with the biocompatible thermosensitive polymer poly(N-vinylcaprolactam) (PNVCL). Silica dispersions (Aerosil OX50) were used as model and evaluated by means of analytical centrifuge, laser diffraction, and turbidimetry studies. Results show that the sedimentation velocity is doubled by addition of PNVCL and that at 45°C the density of the sediment is 33% higher, as compared to the use of CH2500 only. This results from the temperature sensitive behavior of PNVCL that phase-separate expelling water at temperatures higher than its LCST (32–34°C) leading to compaction of the flocs. By using this strategy the sediment is more compact, contains less water, and contains a very small amount of biodegradable CH2500 and biocompatible PNVCL.

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