Heat transfer of high temperature fouling in combustion chambers

In the current economic and political climate it is vital to develop energy saving methodologies as well as protecting the environment. According to recent studies conducted by the European Union, heat exchangers, due to their ubiquity in industry, represent the largest potential area for energy saving. Their efficiency is significantly affected by the build-up of insulating deposits, known as fouling, on their surfaces. We present an image analysis of industrial deposits which confirms their fractal morphology; we exploit these properties to derive an equation governing the fouling resistance which has an explicit dependency on the Sierpinski fractal dimension of the deposit geometry. Using computer simulated deposits, which include the auto-retardation effect of compaction but with no deposit removal, we show that the fouling resistance can not only reach an asymptotic value over time as the mass increases, but in fact can decrease. This is due to the increased connectivity of the constituent particles and reduced insulation as the density increases.