| OCR Text |
Show - 6 - where the model predictions and analysis give good agreement with measured results, it can be concluded that the operation in those cases may indeed be kinetically controlled. Furthermore, the model can then be used in a predictive way to estimate system response to changes in operating conditions such as equivalence ratio, pressure, fuel composition, and others. In the remaining cases where the kinetic model analysis provides trends which are inconsistent with experimental results, it can be concluded that the combustor operation is controlled by physical and/or chemical processes other than chemical kinetics. SYSTEM PARAMETERS Three independent parameters have been used to characterize the model system. The first of these is the composition of the fuel itself. Three fuels have been investigated, including methane, mixtures of methane with ethane (as simulated natural gas), and propane. For each fuel, the second system parameter is the fuel/air equivalence ratio $, the ratio of actual fuel concentration to that required to consume all of the available oxygen. The third variable in the analysis is the mixing ratio f, defined as the mass fraction of fresh fuel and oxidizer in each sample of igniting gas. Since a given sample of gas, before it has begun to reignite, consists of a mixture of fuel, air, and product species from previous cycles, the mass fraction of residual hot products in the reacting sample is (1-f). |
