Thesis (DTech (Electrical Engineering))--Cape Peninsula University of Technology, 2011 / Ultrasonic Velocity Profiling (UVP) is both a method and a device to measure an instantaneous
one-dimensional velocity profile along a measurement axis by using Doppler echography. UVP
is an ideal technique since it is non-invasive, works with opaque systems, inexpensive, portable
and easy to implement relative to other velocity profile measurement methods. Studies have
suggested that the accuracy of the measured velocity gradient close to wall interfaces need to
be improved. The reason for this is due to, depending on the installation method, distortion
caused by cavities situated in front of ultrasonic transducers, measurement volumes
overlapping wall interfaces, refraction of the ultrasonic wave as well as sound velocity
variations. A new ultrasonic transducer, which incorporates a delay line material optimised for
beam forming could reduce these problems (Wiklund, 2007). If these could be addressed, UVP
could be used for the measurement of velocity profiles in complex geometries (e.g. contractions,
valves, bends and other pipe fittings) where the shape of the velocity profile is critical to derive
models for estimating fluid momentum and kinetic energy for energy efficient designs.
The objective of this research work was to optimise the UVP system for accurate complex flow
measurements by evaluating a specially designed delay line transducer and implementing
advanced signal processing techniques.
The experimental work was conducted at the Material Science and Technology (MST) group at
the Cape Peninsula University of Technology (CPUT). This work also formed part of a
collaborative project with SIK - The Swedish Institute for Food and Biotechnology. Acoustic
characterisation of the ultrasonic transducers using an advanced robotic setup was done at SI K.
Different concentrations of the following non-Newtonian fluids exhibiting different rheological
characteristics were used for testing: carboxymethyl cellulose (CMC) solutions, kaolin and
bentonite suspensions. Water was used for calibration purposes.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:cput/oai:localhost:20.500.11838/2183 |
| Date | January 2011 |
| Creators | Kotze, Reinhardt |
| Publisher | Cape Peninsula University of Technology |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | http://creativecommons.org/licenses/by-nc-sa/3.0/za/ |
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