Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
COMBUSTION-TURBULENCE INTERACTION AND ENGINE PERFORMANCE: A CRFD NUMERICAL SIMULATION ON DIRECT-INJECTION SPARK-IGNITION ENGINES
Submission Author:
Gabriel de Andrade Janene Gonini , PR
Co-Authors:
Gabriel de Andrade Janene Gonini, Javier Antonio Mendoza Corredor , Milton Keisy Kouketsu, Miguel Barrientos, Leonel R Cancino, Amir Antonio Martins Oliveira
Presenter: Milton Keisy Kouketsu
doi://10.26678/ABCM.ENCIT2022.CIT22-0062
Abstract
Fuel direct injection (DI) is not a new technology, but its importance has been increasing in recent developments of spark ignition (SI) internal combustion engines (ICE). The development of this and other ICE technologies is better assisted with computational reactive fluid dynamics (CRFD) simulations. The present work assesses a CRFD DI-SI ICE model for combustion and engine performance purposes, more specifically, analyzing the turbulence-combustion interaction. The baseline simulation is one from AVL FIRE's database. It takes into account combustion, species transport, emissions, spray behavior, and wall-film models. The extended coherent flame model (ECFM-3Z) combustion model (3 zones) was used with the Discrete Droplet Model (DDM) spray model. The coherent flame model is based on a laminar flamelet approach, in which flame velocity and thickness are mean values integrated along the flame front, only dependent on the pressure, the temperature, and the stoichiometry of the unburned gases. As such, it decouples chemistry and turbulence; however, the variation on the turbulence model is expected to promote some changes in flow and chemical species fields, which influence the flamelet position and, therefore, the rate of heat release. To assess the influence of the turbulence model, the baseline case is compared to modified cases, changing the turbulence model from k-zeta-f to k-epsilon, for different engine rotations. This led to differences on tangible quantities of interest that evaluate the engine performance and characterize combustion (torque, power, mass fraction burnt and combustion duration). Also, quantities like pressure, temperature, rate of heat release and normalized turbulence intensity aid the comparisons.
Keywords
combustion models, direct-injection spark-ignition internal combustion engines, AVL-Fire, Turbulence Models, turbulence-combustion interaction
