Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Comparison between chemical kinetics and chemical equilibrium approaches for NO and CO formations on spark ignition engine conditions
Submission Author:
Alessandro José Truta Beserra de Lima , SP , Brazil
Co-Authors:
Alessandro José Truta Beserra de Lima, Waldyr Gallo
Presenter: Alessandro José Truta Beserra de Lima
doi://10.26678/ABCM.COBEM2017.COB17-0773
Abstract
A series of theoretical analyses of pollutant formation in combustion processes has been undertaken in a computer program for a closed, isometric and isothermal system. The objective was to study and develop pollutant formation models in Spark-Ignited Engines for a 12-chemical species case. Three similar cases, each considering different chemical species and reactions, were firstly studied to evaluate the composition of the gases, based on chemical equilibrium. Next, the same systems were analyzed on a chemical kinetics methodological approach. The goal was to compare the differences between species concentration and reaction times for different thermodynamic states similarly found in spark ignited engines. Based on the calculated reaction times, situations where chemical kinetics is more coherent than chemical equilibrium are presented. The nonequilibrium effects are analyzed for Nitric Oxide (NO) and Carbon Monoxide (CO), showing how far from equilibrium state they are, depending on the process. Results indicated that NO and CO molar fractions reached proximity to chemical equilibrium for temperatures higher than 2400K at similar engine conditions.
Keywords
NO formation, CO formation, Spark ignition engines, chemical kinetics, Chemical Equilibrium
