A Rheological Model of Semisolid Magnesium Alloy Slurries

2005 ◽  
Vol 488-489 ◽  
pp. 333-336 ◽  
Author(s):  
L. Li ◽  
X.W. Zhou ◽  
J.Y. Chen
Keyword(s):  
Magnesium Alloy ◽  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Rheological Model ◽  
The State ◽  
Simple Shearing ◽  
Flow Conditions ◽  
Rheological Behaviors ◽  
Microstructure Model

In this paper a rheological model is presented which describes the rheological behaviors of liquid-like semisolid magnesium alloy under a simple shearing flow. On the basis of Chen and Fan’s mono-dispersion microstructure model of semisolid metal slurry, the particle size distribution is considered in this model. It is believed that it is the state of agglomeration which determines the rheological behaviors of the slurry, whereas the external flow conditions such as shear rate and shearing time, affect the rheological properties by changing the state of agglomeration. The expressions of collision rate between two agglomerates, effective solid fraction and the formula of apparent viscosity of Chen and Fan’s model are corrected according to the experimental results and statistical mechanics. Finally calculated apparent viscosity and the average number of the particles of AZ91D by the developed model as functions of shear rate are presented. These results show that there is a one to one coupling between the rheological properties of the magnesium alloy slurries and the state of the agglomeration.

Flow Behaviors of High Acyl Gellan Aqueous Solutions as Affected by Temperature, and Calcium and Gellan Concentrations

2008 ◽  
Vol 4 (5) ◽  
Author(s):  
Yiqun Huang ◽  
Pawan Singh Takhar ◽  
Juming Tang ◽  
Barry G Swanson
Keyword(s):  
Shear Rate ◽  
Aqueous Solutions ◽  
Apparent Viscosity ◽  
Flow Resistance ◽  
Effect Of Temperature ◽  
Temperature Changes ◽  
Influence Of Temperature ◽  
Rheological Behaviors ◽  
Low Concentrations ◽  
Influence Of Temperature On

Rheological behaviors of high acyl (HA) gellan are not well understood partially because of its relatively late commercialization compared to low acyl gellan. The objective of this study was to investigate the effect of temperature (5-30 °C), calcium (0, 1 and 10 mM) and gellan concentrations (0.0044-0.1000% w/v) on the flow behaviors of high acyl gellan aqueous solutions using rheological tests. Gellan solutions with 0 or 1 mM added Ca++ exhibited shear thinning behavior at gellan concentrations above 0.0125%. The influence of temperature on apparent viscosity (shear rate, 100 s-1) of gellan solutions can be described with an Arrhenius relationship. The apparent viscosity of gellan solution at low concentrations was more sensitive to temperature changes. The addition of Ca++ led to a decrease in flow resistance for a dilute gellan solution (<0.0125%), but an increased resistance for a relatively concentrated gellan solution (>0.0125%).

Rheological Behavior of Semisolid AlSi6Mg2 Alloy at Transient State

2012 ◽  
Vol 217-219 ◽  
pp. 369-372
Author(s):  
Li Ping Ju ◽  
Ying Wu ◽  
En Sheng Xu ◽  
Wei Wang ◽  
Hong Chao Luo
Keyword(s):  
Shear Rate ◽  
Rheological Behavior ◽  
Rheological Model ◽  
Transient State ◽  
External Flow ◽  
Flow Conditions ◽  
Agglomerate Size ◽  
Resting Time

In the present work, basing on the rheological model of Chen and Fan [1], the rheological behavior of AlSi6Mg2 alloy at transient state is investigated. It has been shown that the deagglomeration of particles is about two orders of magnitude faster than the agglomeration of them. The inequality of agglomeration rate and deagglomeration rate is thought as the origin of the thixotropy of SSMS. Subsequently, the similar trend of the variation of the viscosity and the average agglomerate size with shearing time and resting time shows that the microstructure of SSMS determines its rheological behavior, while the external flow conditions (such as shear rate, shearing time, etc) influence the viscosity by changing its microstructure. The present study predicts that the CF model can describe reliably the transient rheological behavior of AlSi6Mg2 alloy.

Rheology of pulp suspensions of bleached sugarcane bagasse: Effect of consistency and temperature

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 601-606 ◽  
Author(s):  
JORGE H. SÁNCHEZ ◽  
GERMÁN C. QUINTANA ◽  
MERY E. FAJARDO
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Yield Stress ◽  
Sugarcane Bagasse ◽  
Power Law ◽  
Apparent Viscosity ◽  
Power Law Model ◽  
Pulp Suspensions ◽  
Concentric Cylinders ◽  
Rate Controlled

Rheological properties, such as yield stress and apparent viscosity, of pulp suspensions of bleached sugarcane bagasse were studied in a stress-shear rate controlled rheometer using concentric cylinders geometry. Results were statistically analyzed and presented as a function of the suspension consistency (0.5% ≤ Cm ≤ 4.0%) and temperature (20°C, 40°C, and 60°C). The yield stress was influenced by the consistency and temperature. The apparent viscosity was influenced only by the consistency. A power law model was fitted to the experimental results of yield stress. In flow tests, all the suspensions showed shear-thinning behavior, which was in agreement with the Carreau-Yasuda model.

Flow Properties and Melt Distortion in Molten Rubber Compounds under Capillary Extrusion

2013 ◽  
Vol 747 ◽  
pp. 627-630
Author(s):  
Watcharapong Chookaew ◽  
Yanichsa Sukniyom ◽  
Somjate Patcharaphun ◽  
Narongrit Sombatsompop
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Wall Slip ◽  
Skin Layer ◽  
Rubber Compound ◽  
Melt Fracture ◽  
Extrudate Swell ◽  
Rubber Compounds ◽  
Capillary Extrusion

The influences of shear rate and vulcanizing system on the rheological properties and melt fracture of natural rubber compounds were investigated by using a rate-controlled capillary rheometer. The rheological properties of rubber compounds were characterized with respect to the apparent viscosity and extrudate swell. The measured results indicated that the apparent viscosity tended to decrease with increasing shear rate. This was due to the pseudoplastic behavior of molten rubber compound. It was evident that rubber compound using EV system showed the lowest apparent viscosity as compared to those obtained by CV and NS systems, respectively. This was due to the occurrences of premature crosslink at the skin layer and the wall slip of rubber compound during the flow in capillary die. Furthermore, the onset of smooth surface was also observed which depending on the types of crosslink at the skin layer.

The Rheological Behaviors of Nylon610 and Nylon610/Montmorillonite Nanocomposites

2011 ◽  
Vol 183-185 ◽  
pp. 1726-1730 ◽  
Author(s):  
Qian Wang ◽  
Cheng Shen Zhu ◽  
Ping Du ◽  
Su Qin He
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Apparent Viscosity ◽  
Effect Of Temperature ◽  
Pseudoplastic Fluid ◽  
Rheological Behaviors ◽  
Lower Shear ◽  
Lower Shear Rate ◽  
Montmorillonite Nanocomposites

The rheological behaviors of nylon610 and nylon610/montmorillonite nanocomposites had been studied by means of HAAKE-Ⅱrheometer. The results showed that nylon610 and nylon610/montmorillonite composites were pseudoplastic fluid. The non-Newtonian indexes, which were in the range of 0.49～0.82 at differern temperatures, decreased with the addition of montmorillonite. What is more, the apparent viscous activation energy decreased, which showed the effect of temperature on apparent viscosity of the nanocomposites was weaker than that of pure nylon610, apparent viscosity increased with the increase of montmorillonite, especially at the lower shear rate.

Physical and Rheological Properties of Animal Manure: A Review

2018 ◽  
Vol 61 (3) ◽  
pp. 1113-1120
Author(s):  
Ibrahim Denka Kariyama ◽  
Xiaodong Zhai ◽  
Binxin Wu
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
Pressure Head ◽  
Animal Manure ◽  
Anaerobic Treatment ◽  
Pseudoplastic Fluid ◽  
Power Law Equation

Abstract. This literature review was conducted on the physical and rheological properties of animal manure slurries and their applications. The review revealed the importance of these properties in the design of anaerobic treatment plants, pipe systems to transport slurries to treatment and storage units, and other applications and management of raw and treated slurries. The selection of pumping and mixing equipment and their power requirements, the flow behavior, mass, and heat transfer, the quality of mixing, pressure head loss, and other applications of manure slurries are affected by the physical and rheological properties. The review shows that manure slurries generally exhibit non-Newtonian pseudoplastic fluid behavior with a decreasing apparent viscosity as the shear rate increases and that the power law equation can successfully be used to describe the relationship between shear stress and shear rate, especially for low total solids concentrations. Keywords: Animal manure slurries, Apparent viscosity, Non-Newtonian pseudoplastic fluids, Power law equation, Rheological properties.

Characterization of Cellulose Nanocrystal Suspension Rheological Properties Using a Rotational Viscometer

2021 ◽  
Vol 71 (3) ◽  
pp. 290-297
Author(s):  
Yucheng Peng ◽  
Changlei Xia ◽  
Brian Via
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
Cellulose Nanocrystal ◽  
Rotational Viscometer ◽  
Spindle Rotation ◽  
Quality Control Tool ◽  
Calculation Results

Abstract Interest in cellulose nanocrystal (CNC) recently has been growing significantly. Many applications have been developed for CNC and appropriate procedures to handle the CNC suspensions are critical for these applications. In this study, we explored a method evaluating CNC suspensions based on rheological property characterization. We used a rotational viscometer to characterize CNC suspensions at concentrations of 3, 4, 5, and 6 wt.%. We collected primary readings from the rotational viscometer, including spindle rotation speed and torque, to generate apparent viscosity and shear rate for CNC suspensions. We applied three different methods summarized from the literature to calculate apparent viscosity and real shear rate. We critically analyzed differences among calculation results from the three methods. Shearing thinning behaviors obeyed the power law flow model for all CNC suspensions in the shear rate tested. At different concentrations, consistency and flow behavior indices in the model differed in the measured shear rate range. With the same shear rate, higher concentration CNC suspension had a higher apparent viscosity. The apparent viscosity of the CNC suspension was associated with its weight concentration in a power law relationship. This study indicated that a rotational viscometer can be used as a quality control tool for characterizing the rheological properties of the CNC suspensions. We made recommendations for using appropriate calculation methods to obtain shear rate and apparent viscosity of CNC suspensions from the primary readings of a rotational viscometer under different situations.

scholarly journals Rheological Properties of Polysaccharides from Longan (Dimocarpus longanLour.) Fruit

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Xingxun Liu ◽  
Yongyue Luo ◽  
Chunjie Zha ◽  
Sumei Zhou ◽  
Liya Liu ◽  
...  
Keyword(s):  
Shear Rate ◽  
Chemical Analysis ◽  
Rheological Properties ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Small Amplitude ◽  
Flow Behavior ◽  
Viscoelastic Behavior ◽  
Dynamic Shear ◽  
Small Amplitude Oscillatory Shear

Longan polysaccharide (LP) was extracted from longan (Dimocarpus longanLour.) pulp. The composition and rheological properties were determined by chemical analysis and dynamic shear rheometer. The flow behavior and viscoelastic behavior of longan polysaccharide (LP) solution were investigated by steady shear and small amplitude oscillatory shear (SAOS) experiments, respectively. The result shows that the solution is a pseudoplastic flow in a range of shear rate (1–100 s−1). The rheological behavior of LP was influenced by cations such as Na+and Ca2+. With an increase of apparent viscosity,G′andG′′were accompanied by addition of Na+and Ca2+.

Study on the Rheological Properties of PTFE/PVA Blended Solution

2011 ◽  
Vol 233-235 ◽  
pp. 2934-2937
Author(s):  
Yao Wu Wang ◽  
Run Jun Sun ◽  
Zhao Huan Zhang ◽  
Li Ping Chen ◽  
Mu Yao
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Shear Thinning ◽  
Shear Thinning Fluid

PTFE suspension latex and PVA solution are blended at different ratio, and the rotary rheometer is used to test the rheological properties of these solutions. The result shows that both PTFE suspension latex and PTFE/PVA blended solution are all shear thinning fluid; with increasing shear rate, apparent viscosity decreases; with increase of PVA content in blended solution, apparent viscosity and Non-Newtonian index increase, and spinnability of blended solution can be improved; with increase of temperature, the apparent viscosity decreases.

Rheological Properties of all Para-Position Polysulfonamide Spinning Solutions

2014 ◽  
Vol 941-944 ◽  
pp. 1233-1236
Author(s):  
Hu Min Li ◽  
Jiong Xin Zhao
Keyword(s):  
Mechanical Properties ◽  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Solvent System ◽  
Para Position ◽  
Aprotic Solvents ◽  
Terephthaloyl Chloride ◽  
Static State

Our previous research showed that the presence of more rigid segments of p-phenylene in the PSA copolymer backbone enhanced the strength and modulus of the fiber. Poly (4,4'-diphenylsulfone terephthalamide) referred to as all para-position PSA, which was synthesised only by 4,4'-diaminodiphenylsulfone (4,4’-DDS) and terephthaloyl chloride (TPC), and it was expected to have best mechanical properties. As it cannot be easily dissolved in common amide-type polar aprotic solvents, N,N-dimethylacetamide (DMAc)/LiCl and DMAc/CaCl2 solvent system was used to solve this problem. Static state rheological properties of all para-position PSA spinning solutions were investigated by measuring the apparent viscosity versus shear rate at different concentrations and temperatures. The effectiveness of cosolvent like LiCl and CaCl2 in the solvent system were investigated, the results showed that LiCl was more effective than CaCl2.

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