Modeling Chemical Reactors I: Quiescent Reactors

TL;DR

This paper introduces a generalized numerical framework for modeling quiescent chemical reactors in 1D, 2D, or 3D, emphasizing entropy-preserving adaptivity and applying it to complex reaction systems like the Belousov-Zhabotinskii reaction.

Contribution

It develops a novel operator splitting scheme with hp-adaptivity based on entropy, enabling stable and accurate simulations of complex chemical kinetics in arbitrary space dimensions.

Findings

Successfully applied to classical nonequilibrium thermodynamics problems.

Demonstrated stability through entropy-preserving adaptivity.

Achieved accurate numerical error evaluation in equilibrium scenarios.

Abstract

We introduce a fully generalized quiescent chemical reactor system in arbitrary space $\vdim =1,2$ or 3, with $n\in\mathbb{N}$ chemical constituents $\alpha_{i}$, where the character of the numerical solution is strongly determined by the relative scaling between the local reactivity of species $\alpha_{i}$ and the local functional diffusivity $\mathscr{D}_{ij}(\alpha)$ of the reaction mixture. We develop an operator time-splitting predictor multi-corrector RK--LDG scheme, and utilize $hp$-adaptivity relying only on the entropy $\mathscr{S}_{\mathfrak{R}}$ of the reactive system $\mathfrak{R}$. This condition preserves these bounded nonlinear entropy functionals as a necessarily enforced stability condition on the coupled system. We apply this scheme to a number of application problems in chemical kinetics; including a difficult classical problem arising in nonequilibrium thermodynamics known as the Belousov-Zhabotinskii reaction where we utilize a concentration-dependent diffusivity tensor $\mathscr{D}_{ij}(\alpha)$, in addition to solving a simple equilibrium problem in order to evaluate the numerical error behavior.