Advanced quasi-steady state approximation for chemical kinetics

TL;DR

This paper introduces an advanced quasi-steady state approximation for chemical kinetics that improves upon classical methods, enabling more efficient and accurate reduction of complex reaction systems in turbulent reacting flows.

Contribution

It develops a new QSSA based on invariant manifold theory that is independent of species choice and adaptable for various objectives, enhancing computational feasibility.

Findings

Improved physical and mathematical properties of the new QSSA.

Independence from the selection of slow species.

Enhanced suitability for unsteady turbulent flow simulations.

Abstract

Computational feasibility of turbulent reacting flows hinges on the reduction of large chemical kinetics systems to smaller more manageable reaction sets. Recently, several sophisticated reduction techniques have been developed but they continue to be computationally prohibitive for practical three-dimensional unsteady computations. For such applications, the classical quasi-steady state assumption (QSSA), despite serious shortcomings, continues to be popular due to its conceptual clarity and computational simplicity. Starting from invariant manifold description, we develop an advanced quasi-steady state assumption which (i) is independent of the choice of the retained (slow) species; (ii) possesses much improved physical and mathematical characteristics; and (iii) can be specialized for any objective function.