It has been observed in both small-scale experiments and full-scale fuel system simulators that jet fuels, when heated, undergo chemical reactions that eventually result in sediment/deposit formation. Thus, the thermal stability of jet fuels has the deleterious effect of causing fuel system malfunctions. This situation is also possible in supersonic aircraft, where an increase in the metal skin temperature due to aerodynamic heating can, in turn, increase the temperature of uninsulated fuel tanks, leading to deposit formation. Although a great deal of experimental data has been obtained, the exact mechanisms of the degradation reaction and the consequent deposit formation process are still largely unknown. This is primarily due to the fact that the degradation process is influenced by many factors, some of which cannot be determined, varied or controlled in an experiment. Thus, there is a need for a mathematical model that can be used to predict the fuel deposition process by combining the effects of the fluid flow and heat transfer processes and the fuel degradation reactions. In this Phase I study, a simple mathematical model will be developed using available information on the various unit processes involved in the deposit formation process. Sample problems based on existing experimental data will be solved using this model, and the results will be validated with available experimental data.
