This thesis is concerned with a theoretical and experimental
study of the hydrodynamics and heat transfer characteristics
of viscous fluids flowing in tubes under laminar conditions.
Particular attention has been given to the effects of the rheological
properties and their variation with temperature. A review of
problems of this type showed that in spite of the many potential
applications of the results in a wide range of industries
the subject had not been well developed and further work is justified in order to fill some of the gaps in our knowledge.
The early part of the thesis considers the justification of the
work in this way and sets down the scope and objectives. A computer progracune was then developed to allow the
governing equations of the problem to be solved numerically to
give the velocity and temperature profiles and pressure drop for
both heating and cooling conditions. The results were also
presented in the form of Nusselt numbers as a function of the
Graetz numberp since this form is useful for engineering design
purposes. The validity of the predictions were then checked by a
programme of experimental work. Temperature and velocity profiles
have been measured in order to provide a more severe test of the
theory than could be imposed by the measurement of overall heat
transfer rates. A combined thermocouple probe/Pitot tube was
developed to allow simultaneous measurements of velocity and
temperature to be made. A Newtonian oil and two non-Newtonian
Carbopol solutions were studied. This is the first time that
velocity and temperature profiles have been measured for non-Newtonian
fluids in this type of situation. The results of the work heve shown that
(a) the velocity and temperature profiles and pressure
drops are greatly affected by the temperature dependence
of the rheological properties and since real viscous
fluids are normally very temperature-sensitive it is
important that this effect is properly taken into
account.
(b) the engineering design correlations commonly used for
the prediction of heat transfer coefficients can be
seriously in error, especially for cooling conditions
and when non-Nevitonian fluids are being considered.
(c) a mathematical model can be developed which accurately
describes all the phenomena and gives predictions which
are very close to those observed experimentally. An important objective was to develop more accurate engineering
design correlations for non-isothermal pressure drop and heat
transfer rates. / University of Bradford
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/4204 |
| Date | January 1975 |
| Creators | Pavlovska-Popovska, Frederika |
| Contributors | Wilkinson, W.L. |
| Publisher | University of Bradford, Postgraduate School of Studies in Chemical Engineering. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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