INITIATION OF CaSO4 SCALE FORMATION ON HEAT TRANSFER SURFACES UNDER POOL BOILING CONDITIONS

The success of innovative fouling mitigation techniques such as ion implantation depends upon early stage of scale formation on heat transfer surface. This is because the first crystalline nuclei that appear on the surface during the initial period dictate how fouling would develop in latter stages. In this study, the initial period of deposition of calcium sulphate on heat transfer surfaces has been investigated under pool boiling conditions. The independent variables were heat flux and calcium sulphate concentration. The experimental results show that the time until the heat transfer coefficient reaches its intermediate maximum decreases with increasing concentration and heat flux, and is also significantly affected by the surface finish. Neural network architectures were utilized to correlate the experimental results during the initial deposition period. A satisfactory agreement between predicted and measured heat transfer coefficients has been achieved with an average error of 8.7%.