An accurate method based on the evolutionary centers algorithm for optimizing chemical-diffusive models for flame acceleration and DDT

This paper presents an accurate method based on the Evolutionary Centers Algorithm (ECA) for determining the optimal reaction and diffusion parameters for Chemical-Diffusive Models (CDM) to simulate flame acceleration (FA) and deflagration-to-detonation transition (DDT). The proposed method leverages the global search capability of the ECA and the local optimization strength of the Nelder-Mead (NM) algorithm. The hybrid approach (ECA-NM) reliably determines CDM parameters that reproduce the major properties of combustion waves. The CDMs for premixed flames and detonations of hydrogen in air or oxygen were developed using the present ECA-NM method and validated against canonical tests of combustion waves and previous experiments of FA and DDT. The results show that the major flame and detonation properties calculated using the developed CDMs match those obtained from detailed chemical reaction mechanisms over a wide range of equivalence ratios. The simulated FA and DDT in a channel also agree qualitatively and quantitatively with experiments in terms of complex flame instabilities (e.g., tulip and distorted tulip flames), flame displacement speed, and detonation occurrence. In addition, detailed comparisons to the traditional genetic algorithm demonstrate that the center-of-mass-guided search of the ECA-NM escapes the local minima that trap the stochastic genetic algorithm and diminishes the global error by nearly four orders of magnitude. This work provides an efficient and reliable method for developing CDMs that allows quantitative multiscale simulations of transient flames and detonations in complex scenarios.