View in EDS

Necessary and Sufficient Conditions for Accurate Reduced Kinetic Mechanisms to Have Fidelity in Reactive Flow Simulations.

Saved in:

Bibliographic Details
Title:	Necessary and Sufficient Conditions for Accurate Reduced Kinetic Mechanisms to Have Fidelity in Reactive Flow Simulations.
Authors:	Bellan, Josette¹ (AUTHOR) jbellan@caltech.edu
Source:	Combustion Science & Technology. 2026, Vol. 198 Issue 6, p1628-1669. 42p.
Subject Terms:	Reactive flow, Chemical kinetics, Navier-Stokes equations, Chemical species, *Oxidation kinetics
Abstract:	To date, there is still an inability to efficiently solve the Navier–Stokes equations for reactive flows in conjunction with lengthy and complex chemical kinetics describing oxidation of realistic fuels. Therefore, reduced kinetic mechanisms are sought that are as compact as possible, so as to reduce the number of species equations solved. However, there is a quandary for flow simulations as to whether compact reduced mechanisms could emulate hypothetical flow simulations using the template kinetics from which the reduced mechanism was obtained. In this study, necessary and sufficient conditions are derived for this emulation to occur. The proposed concepts, self-similarity and partitioning the ensemble of species into computed and non-computed species, are the building blocks of the chemical kinetic reduction in the Local Self-Similarity Tabulation method. It is shown that employing the same species partitioning concept for flow simulations must be accompanied by several conditions which must be satisfied for the simulation to be a good approximation of the hypothetical simulation using the template kinetic mechanism. These conditions represent the necessary and sufficient conditions criteria. There are indications from the literature that these criteria are not necessarily satisfied. A protocol is proposed for checking whether these conditions are fulfilled for any selected reduced mechanism. Several possibilities are advanced to palliate for lack of fulfillment of these criteria. Research gaps are identified that must be filled to enable successful utilization of reduced mechanisms in reactive flow simulations, and procedures to mitigate these gaps are outlined. [ABSTRACT FROM AUTHOR]
Database:	Energy & Power Source

Description
Abstract:	To date, there is still an inability to efficiently solve the Navier–Stokes equations for reactive flows in conjunction with lengthy and complex chemical kinetics describing oxidation of realistic fuels. Therefore, reduced kinetic mechanisms are sought that are as compact as possible, so as to reduce the number of species equations solved. However, there is a quandary for flow simulations as to whether compact reduced mechanisms could emulate hypothetical flow simulations using the template kinetics from which the reduced mechanism was obtained. In this study, necessary and sufficient conditions are derived for this emulation to occur. The proposed concepts, self-similarity and partitioning the ensemble of species into computed and non-computed species, are the building blocks of the chemical kinetic reduction in the Local Self-Similarity Tabulation method. It is shown that employing the same species partitioning concept for flow simulations must be accompanied by several conditions which must be satisfied for the simulation to be a good approximation of the hypothetical simulation using the template kinetic mechanism. These conditions represent the necessary and sufficient conditions criteria. There are indications from the literature that these criteria are not necessarily satisfied. A protocol is proposed for checking whether these conditions are fulfilled for any selected reduced mechanism. Several possibilities are advanced to palliate for lack of fulfillment of these criteria. Research gaps are identified that must be filled to enable successful utilization of reduced mechanisms in reactive flow simulations, and procedures to mitigate these gaps are outlined. [ABSTRACT FROM AUTHOR]
ISSN:	00102202
DOI:	10.1080/00102202.2025.2513968