Development of a volumetric flow rate set-up used for the evaluation of a permanent magnet and the effect it has on scale formation in a tube

Abstract

Paper presented to the 1st International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Kruger Park, 8-10 April 2002.An experimental investigation is described in which an experimental set-up 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 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 Physical Water Treatment (PWT) device and the other two tubes are used as a control. With the experimental set-up described it is possible to detect a change in the friction factor of 1% which represents a flow rate change of 22 m f !min. Experiments are conducted in different phases in which the PWT device is attached onto one of the tubes and then removed to determine if any change in the scale formation rate takes place. It follows from the results obtained that a very sensitive experimental set-up was designed and built with which very small amounts of scale can be detected. However, contradictions in the experimental results makes the set-up unusable for the evaluation of the efficiency of PWT devices.