Physical interpretation on development and validation of the reaction routes of complex chemical kinetic model

Simulating the complexity in its entirety proves highly challenging, to examine both the local and global stability of the model, as well as its positivity, recognizing the overall instability. To address this challenge, a strategy of splitting down the multi-route complex reactions into its independent sub-routes is employed. For the validation of sub-routes, the stability and positivity of each individual route were comprehensively analyzed. In addition, we employ techniques to simplify our models by considering factors such as reaction speed and thermodynamic properties, ensuring their accuracy. Furthermore, we integrate the Spectral Quasi-Equilibrium Manifold to obtain a deeper understanding of the sequential advancement of reactions, focusing on the slowest eigenvector. A comprehensive examination of the mathematical underpinnings of these reaction steps and diverse pathways is conducted. We also investigate the temporal behavior of these pathways, yielding fresh perspectives. Our findings suggest the feasibility of independently evaluating each pathway rather than treating the entire mechanism as a singular entity. To enhance our analysis, we conduct a local sensitivity assessment using the SimBiology toolbox in MATLAB of each route and compare calculation periods for TRM (Total Relative Motion). Furthermore, we employ the short-time Fourier transform graph to capture time–frequency information regarding the steady state of compounds in various routes, revealing spectral variations over time.