dc.contributor.author |
T’Joen, C.
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|
dc.contributor.author |
Rohde, M.
|
|
dc.contributor.author |
De Paepe, M.
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dc.date.accessioned |
2014-12-08T12:21:45Z |
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dc.date.available |
2014-12-08T12:21:45Z |
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dc.date.issued |
2012 |
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dc.description.abstract |
Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012. |
en_ZA |
dc.description.abstract |
Because of their unique properties, supercritical fluids are becoming increasingly popular for industrial applications. These fluids behave liquid like at low temperatures and gas like at higher temperatures, with a smooth transition in between. This makes them very suited as a solvent for chemical extraction and separation processes. Another important use is as a power fluid. Modern fossil fuel fired power plants all operate using supercritical water, and on a smaller power scale they are considered for organic rankine cycles and refrigeration. As they heat up, the density of a supercritical fluid changes shows a very sharp drop for temperatures close to the critical point. This large density difference can be used as the driving force to circulate the fluid in a loop, rather than using a pump. This idea is similar to natural circulation boiling loops, but the density difference is larger. It adds a layer of inherent safety to a design, as active components such as pumps are no longer required; but also adds an additional complexity: flow instabilities. It is well known from natural circulation boiling systems, that these loops can become unstable under certain conditions (e.g. high power and low flow rate). In this study, a simple supercritical loop is studied to determine the neutral stability boundary. This is done through linear stability analysis: the set of one-dimensional governing equations is first linearised and then the eigenvalues are determined. These describe the response, indicating if it is stable or not. The results indicate that there is a clear unstable area, which can be linked to different types of instabilities. |
en_ZA |
dc.description.librarian |
dc2014 |
en_ZA |
dc.format.extent |
9 pages |
en_ZA |
dc.format.medium |
PDF |
en_ZA |
dc.identifier.citation |
T’Joen, C, Rohde, M & De Paepe, M 2012, Linear stabitlity analysis of a supercritical loop, Paper presented to the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012. |
en_ZA |
dc.identifier.isbn |
9781868549863 |
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dc.identifier.uri |
http://hdl.handle.net/2263/42869 |
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dc.language.iso |
en |
en_ZA |
dc.publisher |
International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics |
en_ZA |
dc.relation.ispartof |
HEFAT 2012 |
en_US |
dc.rights |
University of Pretoria |
en_ZA |
dc.subject |
Supercritical fluids |
en_ZA |
dc.subject |
Liquid like at low temperatures and gas like at higher temperatures |
en_ZA |
dc.subject |
Chemical extraction |
en_ZA |
dc.subject |
Power fluid |
en_ZA |
dc.subject |
Supercritical water |
en_ZA |
dc.subject |
Rankine cycles |
en_ZA |
dc.subject |
Density difference |
en_ZA |
dc.subject |
Natural circulation boiling loops |
en_ZA |
dc.subject |
Flow instabilities |
en_ZA |
dc.subject |
High power and low flow rate |
en_ZA |
dc.subject |
Supercritical loop |
en_ZA |
dc.subject |
Linear stability analysis |
en_ZA |
dc.title |
Linear stabitlity analysis of a supercritical loop |
en_ZA |
dc.type |
Presentation |
en_ZA |