Rheological properties of starch suspensions using a rotational rheometer fitted with a starch stirrer cell

2014 ◽  
Vol 53 (3) ◽  
pp. 255-267 ◽  
Author(s):  
Anne Matignon ◽  
Fabrice Ducept ◽  
Jean-Marc Sieffermann ◽  
Philippe Barey ◽  
Marc Desprairies ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Rotational Rheometer

scholarly journals Use of helical ribbon mixer for measurement of rheological properties of fruit pulps

2013 ◽  
Vol 19 (No. 4) ◽  
pp. 148-153 ◽  
Author(s):  
P. Novotná ◽  
A. Landfeld ◽  
K. Kýhos ◽  
M. Houška ◽  
J. Strohalm
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Flow Behaviour ◽  
Rotational Rheometer ◽  
Shear Rates ◽  
Coaxial Cylinders ◽  
Helical Ribbon ◽  
Flow Behaviour Index ◽  
Average Shear ◽  
Behaviour Index

Fruit pulps contain fine particles of the flesh of the original fruit that are suspended in the fruit juice. This suspension has a tendency to settling or separation during measurements of its rheological properties in the rotational rheometer with coaxial cylinders (especially if the greater gap is used). In this case the use of a mixer is convenient. The mixer can serve as a tool for measurement of rheological properties and at the same time it can prevent the settling and it is not sensitive to the occurrence of greater particles in the measured fluid. The helical ribbon mixer was used in this work for measurement of five samples of fruit pulp. The mixer was calibrated by the use of Newtonian fluid of known viscosity (honey). The radius of the inner cylinder of hypothetical rotational rheometer was predicted from the assumption that mixer and cylinder exhibit the same torque necessary for the rotation at the same rotational speed. The average shear rate in the mixed pulp was predicted by using the relation valid for power law fluids and rheometer with coaxial cylinders. The radius (where the average shear rate was calculated) was chosen by the requirement that the shear rate would be almost independent of changes in the flow behaviour index valid for measured pulps. Firstly the flow behaviour index was predicted as a slope of torque vs. rotational speed dependence in log-log co-ordinates. It was found that the flow behaviour index varies in the range 0.2–0.3. The radius was predicted from a graph where shear rates for 0.2 and 0.3 are the same. Then the average shear rates were calculated from rotational speeds for individual flow behaviour indexes. Rheological properties measured by using a mixer correspond to those measured with a rotational rheometer with coaxial cylinders satisfactorily only in the case that the creeping flow regime was kept in the mixed fluid. The fruit pulps are strongly non-Newtonian fluids with very low values of the flow behaviour index around 0.2.

Rheological Characteristics of Solvent-Cast Poly(e-Caprolactone)/Organoclay Nanocomposite

2007 ◽  
Vol 121-123 ◽  
pp. 1455-1458
Author(s):  
Cheng Hai Hong ◽  
C.H. Lee ◽  
J.S. Choi ◽  
S.M. Hong ◽  
Hyoung Jin Choi
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Physical And Mechanical Properties ◽  
Rheological Characteristics ◽  
Solution Intercalation ◽  
Rotational Rheometer ◽  
Internal Structures ◽  
Solvent Cast

As an effective way to enhance various properties of polymer, polymer/clay nanocompoiste is being adopted since it can hybrid the properties of the two components, showing superior physical and mechanical properties. In this study, poly(ε-caprolactone) (PCL) nanocomposites using an organoclay were prepared by a solution intercalation method, and their unique internal structures and rheological properties induced by the presence of organoclay at nano level were studied using WAXD and a rotational rheometer.

Steady and Dynamic Rheological Properties of Dense Slurries of Chlorella vulgaris

2011 ◽  
Author(s):  
Alex Breckel ◽  
Altan Ozkan ◽  
Halil Berberoglu
Keyword(s):  
Shear Modulus ◽  
Rheological Properties ◽  
Chlorella Vulgaris ◽  
Flow Characteristics ◽  
Biofuel Production ◽  
Elastic Behavior ◽  
Gel Point ◽  
Rotational Rheometer ◽  
Packing Factor ◽  
Dynamic Rheological Properties

This experimental study reports the steady and dynamic rheological properties of dense slurries of the green algae Chlorella vulgaris. Biofuel production from algae growth is a promising technology that has the potential to serve as a significant component of the world’s revised energy mix. Along with providing a renewable fuel source, algae production acts as a CO2 sink, potentially reducing net CO2 emissions. Design and operation of algae biofuel production facilities require accurate knowledge of the flow characteristics of algae slurries and estimation of the pumping and harvesting energy requirements. Reliable rheological data is needed to optimize production processes to lower costs and increase yields. This study reports steady state viscosity measurements conducted using the ARES TA rotational rheometer using the common algae strain Chlorella vulgaris over the packing factor range from 0.1 to 0.8. Viscoelastic data was gathered using oscillatory tests conducted on the rotational rheometer with a double wall coquette fixture geometry. Dynamic frequency sweep tests were used to recover the storage shear modulus (G′), and the loss shear modulus (G″), which correspond to the elastic and viscous properties of the fluid, respectively. Apparent viscosity of the cell suspensions increased with increasing packing factors. Packing factors lower than 0.3 exhibited Newtonian characteristics, whereas at larger packing factors the behavior was shear-thinning. The algae suspensions exhibited both viscous and elastic behavior when subjected to oscillatory flow, behaving as a dilute solution. Finally, the frequency of the gel point increased with increasing packing factor.

scholarly journals Pressure Drop Method as a Useful Tool for Detecting Rheological Properties of Non-Newtonian Fluids during Flow

2021 ◽  
Vol 11 (14) ◽  
pp. 6583
Author(s):  
Kacper Kaczmarczyk ◽  
Joanna Kruk ◽  
Paweł Ptaszek ◽  
Anna Ptaszek
Keyword(s):  
Pressure Drop ◽  
Rheological Properties ◽  
Flow Rate ◽  
Pressure Sensors ◽  
Newtonian Fluids ◽  
Measuring System ◽  
Flow Meter ◽  
Rotational Rheometer ◽  
Drop Method ◽  
Measuring Section

The aim of the research was to develop a pressure drop measuring method dedicated to fluids under real flow through a pipeline. The measurement system is a set of appropriately configured flow meter and pressure sensors installed on the pipeline. The pressure drop values detected on the measuring section are sufficient to clearly determine the rheological properties of the fluid. The measuring system used for the tests consisted of a screw pump, two pressure sensors and an electromagnetic flow meter. The length of the measuring section was 4.12 m, and the internal diameter of the pipeline was 0.026 m. To calibrate of the measuring system a glycerol was used. As a model fluid, a 1% water solution of xanthan gum was used and was subjected to the flow at following shear rate conditions: 5, 11, 17, 23, 29, 35, 41, 47, 53, 59, 65 s−1. The obtained raw experimental data included the pressure drop values and flow rate and they created full information about the fluid behavior during flow. According to the momentum balance equation, the rheological parameters of Ostwald de Waele model were estimated. The estimation procedure was carried out with the help of the Marquardt-Levenberg minimisation method. The same solutions simultaneously were tested with the help of a rotational rheometer. The data obtained from the pressure drop method were consistent with the results obtained from the rotational rheometer. The use of the pressure drop allows to determine the rheological properties of the non-newtonian fluids under the process conditions directly in the pipeline. In addition, it is possible to perform full rheological characteristics based on one flow rate under laminar conditions.

Sign in / Sign up

Export Citation Format

Share Document