M.Ing. / Fouling and more specifically scaling is one of the most discussed and not yet well understood problems facing engineers. Scale formation which has enormous economic and environmental consequences does not only influence heat transfer characteristics and pressure drop through tubes, but influence the volumetric flow rate as well. To solve this problem Physical Water Treatment (PWT) devices have been developed which reportedly reduce scale formation. The efficiency of PWT devices is a controversial subject and many contradictions exits in the claimed effect. Researchers have been trying to prove the efficiency of PWT devices but in most cases the results are typically characterised by low reproducibility. An experimental measuring technique is thus required to measure scale formation and the influence PWT devices has on scaling. This technique must also produce reproducible results to clarify the questions surrounding PWT devices. This thesis is an experimental investigation in which an experimental setup and measuring technique is developed. It is used to evaluate a permanent magnet for the decrease of scale formation in tubes. The volumetric flow rate is used as the indicator of scale formation, which relies on the basic principle that the friction pressure drop increases if scaling takes place. The volumetric flow rate is monitored by measuring the time necessary to fill a container of known volume. The test section consists of three soft drawn copper tubes in which water with a velocity of ± 2 m/s flows. One of the tubes is used to evaluate the PWT device and the other two tubes are used as a control. The water temperature is kept at 53°C. The experiments are done in five phases in which the PWT device is placed onto one of the tubes in phase four and removed in phase five. It follows from the results obtained that a very sensitive experimental setup was designed and built which can be used to evaluate the efficiency of PWT devices. It follows from the variation in time necessary to fill the container in phase four and five that a clear conclusion can not be made. More experiments must be done in which reproducible results are obtained.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:9354 |
| Date | 15 August 2012 |
| Creators | Da Veiga, Reinaldo |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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