Heat transfer fouling through growth of calcareous film deposits

Abstract

The fouling of heat-transfer equipment surface area results in the equipment being overdesigned some 30 per cent. This added metal and size costs the United States about $400 million dollars per year. Consequently, there is a great incentive to better predict the growth of deposits or films on surfaces. The growth of calcareous deposits on metal surfaces is predicted through the application of fundamental principles of fluid mechanics and forced convective mass transfer of dissolved oxygen in water. The film thickness was the single most important variable affecting surface transport rate and growth distribution. The idealized case of a bare cylinder maintained at a constant surface concentration with a diffusion barrier series with the concentration boundary layer is taken as the model. Experimentally the growth of the diffusion barrier with time and the complicating effects of hydrodynamics were studied in the laboratory using spherical electrodes placed in a flowing sea water system. The model is used to predict the experimentally measured current decay.