Elementary and derived sensitivity information in chemical kinetics

This paper considers the use of sensitivity analysis in the elucidation of the interdependence of the variables of a kinetic mechanism. After a brief consideration of elementary sensitivity coefficients (i.e., partial derivatives of species concentrations with respect to rate constants), attention is focused on an entire new family of derived coefficients capable of exhibiting important aspects of the underlying dynamics. Derived coefficients are easily obtained from elementary sensitivities in a way that is completely independent of how the latter quantities are obtained. Each derived sensitivity coefficient has a unique physical interpretation in terms of an experiment or modeling calculation. As an illustration, a reduced kinetic model for the wet oxidation of carbon monoxide is fully discussed in terms of elementary and derived sensitivity information. It is shown that, even for this simple mechanism, the inspection of the derived coefficient profiles reveals useful information about chemical kinetic behavior that cannot be addressed in the (first- and second-order) elementary coefficient framework alone.