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ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
Use of Virtual Kinetics Chemistry for Ignition Delay Times Predictions
Submission Author:
Augusto Finger Pacheco , SC , Brazil
Co-Authors:
Augusto Finger Pacheco, Amir Antonio Martins Oliveira
Presenter: Augusto Finger Pacheco
doi://10.26678/ABCM.ENCIT2020.CIT20-0633
Abstract
The simulation of complex reactive flows usually associated with the applications of combustion generally requires a large amount of computational power, and the reactive part of the solution is usually the most time consuming. Detailed chemical kinetics mechanisms can reach up to tens of thousands species, while numerical simulations of complex reactive flows can handle mechanisms, at most, with a few hundred species. Virtual kinetic mechanisms are a very effective strategy to drastically reduce the computational time spent in the reactive part of numerical simulations. They are formed by artificial species and reaction paths, built from scratch, that are optimized to reproduce the important characteristics of a canonical problem of interest. This work presents the development of a virtual mechanism able to reproduce the temperature evolution and ignition delay times of the thermal ignition of a homogeneous, constant mass, constant pressure, adiabatic, fuel-air mixture. Three different reaction structures are built for a methane-air mixture and their predictions are tested over a range of temperatures from 1000 K to 1500 K and pressures from 1 atm to 3 atm. The limitations observed are due to the small number of reactions and parameters of the kinetic model. But, mechanism reduction methodologies, such as DRG, may present much larger errors if used to achieve the same size of the virtual mechanisms used here.
Keywords
Ignition delay times, Reduced Kinetic Mechanism, virtual chemistry
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