- 41 views
- 108 downloads
Shear Thinning Biopolymers Fluids in a Taylor-Couette Flow
-
- Author / Creator
- Baessa, Muaadh Ali
-
The current study investigates the effect of shear thinning rheology characteristics of high
viscosity non-Newtonian biopolymers on the flow regime characterizations in Taylor Couette
flow. The rheology measurements were carried out to investigate the viscoelastic properties of the
biopolymers prior to the flow visualization experiments.
Both concentrated xanthan gum (XG) and guar gum (GG) solutions were used in this study to
investigate their pseudoplastic rheology properties in aqueous solutions over various ranges of
concentrations from 0.1%wt to 4%wt. The flow curve and viscoelastic frequency sweep
experiments were used to study the rheology of the concentrated biopolymers. The flow curve was
performed over the shear rate range of 0.1 s- 1 to 100 s-1 whereas the frequency sweep was
performed over the frequency of 0.1 to 300 rad/s. The rheology experiments were performed using
a cylindrical head rheometer manufactured by Anton Paar model number NCR-302.
The effect of storage time on the solution viscosity and yield stress of both solutions for the
concentration of 1%wt was also investigated, with successive viscosity and yield stress stability
progress obtained after performing the experiments at the end of each week and after up to 4 weeks
of storage period. Additionally, an extra agitation time was applied for the solutions, and it was
evaluated three different times 8 h, 24 h, and 48 h of continuous agitation time.
After the rheology analysis, the flow visualization investigations experiments using a Taylor
Couette system were performed, aiming to study the flow transition characteristics in the Taylor
Couette system with a fixed outer cylinder and a rotating inner cylinder. The experiments focused
on the flow mapping structure at the onset of each bifurcation for non-Newtonian solutions. We
link the flow characterization transition of the shear thinning solutions in the Taylor Couette flow
to the viscoelastic and yield stress properties obtained from the rheology analysis for each
concentrated solution. Additionally, the flow mapping experiment aims to investigate the effect
of the rheology viscoelastic properties such as the shear thinning flow index (n) on the flow
mapping main parameters such as critical Reynolds number Re, and the azimuthal variations in
the vortex wavelength and vortex count.
The Taylor Couette (TC) flow system has numerous applications which depend on the concept of
a rotating inner cylinder, including science, engineering, industrial, and fluid processes
applications. The TC system is of great interest in the oil field where understanding in needed of
the viscoelastic properties of the non-Newtonian fluids that are used as drilling. Additives may3 | Page
contribute to the transport of sediments outside the well, by using inducing high viscous muds.
The Taylor Couette system is a proper prototype to conduct experiments similar to the downhole
walls and rotating string by considering the borehole wall as the outer cylinder and the rotating
string as the inner cylinder. Additionally, the Taylor Couette system is also observed in various
types of engineering applications, including journal-bearing lubrication, cooling of rotating
machinery among others, and purification of industrial wastewater. -
- Subjects / Keywords
-
- Graduation date
- Fall 2022
-
- Type of Item
- Thesis
-
- Degree
- Master of Science
-
- License
- This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.