F Phenols/sulphur compounds

Dowabstraction of the Darwinian principle of survival of the fittest in order to “breed ” good solutions over a predefined number of “generations”. Deposition rates for a given fuel which have been measured experimentally over a range of conditions are reproduced by solving the conservation equations of mass, momentum, energy and species using a CFD code and the optimised set of rate constants obtained using a genetic algorithm inversion process. The new set of rate constants lie within predefined boundaries based upon previous values found in the literature for the mechanism being used. In addition, this powerful technique promises the ability to develop reaction mechanisms whose newly optimised rate constants reproduce closely all the experimental data available, enabling a greater confidence in their predictive capabilities. The process is also shown to be an effective tool to facilitate the elucidation of shortcomings in current global chemistry models of fuel degradation. Therefore, the results of this study demonstrate that the genetic algorithm inversion process may be used to develop and calibrate more detailed models for the thermal stability behaviour of aviation fuels than have been seen previously and, subsequently, accurately predict the locations and rates of deposit build-up in fuel handling systems. Furthermore, it has been demonstrated that, modern high speed computers allow for evaluation of increasingly complex and expensive GA objective functions. s ki Reaction rate for the ith reaction nchild Number of offspring ne Elitism parameter npop Population siz