Through Computational Fluid Dynamics (CFD), this thesis was undertaken in order to discover a flow modifying geometry to alleviate the underlying hydrodynamic parameters associated with the erosion-corrosion of heat exchanger headers at the Queensland Alumina Ltd Plant (QAL). The process of erosion-corrosion is comprised of two fundamental phenomena; corrosion, the degradation of a material due to it5 electrochemical reaction with its environment, otherwise known as oxidation, and erosion, which finds its roots in the Latin verb "rodene", which means to gnaw, or wear away gradually.
It was found that the CFD model of the heat exchanger header provided reliable results, being comparable to past theses and experimental data [13, 28]. This was not however, reflected in the region of the tube bank, with the CFD modelling of the porous media not providing an adequate representation of the flow through the tube bank, as the inertial resistance factor, equation 4.32, is a linear representation of the inertial losses through the tube bank and should be non-linear according to the development of flow through the tubes.
The characteristic flow parameter, kinetic energy of turbulence, was targeted as the primary agent in the damage caused to the headers by means of erosion-corrosion. Four successively varying geometries were constructed in a bid to reduce the levels of turbulent kinetic energy throughout the header. These geometries consisted of fins placed on the shell of the heat exchanger header, and the incorporation of the prismatic flow correction device devised by Lai . Favourable results were obtained in the final model, however small localised areas of intense turbulence were noticed near the baffle. The final model should provide an alternative geometry to aid in increasing the service life of the headers, however, the need for further study into the detriment of the headers from this small area of high turbulence should be carried out before costly alterations are made.