Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
CFD Flamelet Application of Non-Premixed Diesel Turbulent Combustion: Droplet Size Influence
Submission Author:
Raul Vanz , RS
Co-Authors:
Raul Vanz, Paulo Rodolfo Buffon Ortiz, Paulo Smith Schneider, Cristiano Vitorino da Silva
Presenter: Raul Vanz
doi://10.26678/ABCM.COBEM2019.COB2019-1699
Abstract
This work presents a tridimensional numerical simulation of the non-premixed combustion of diesel in atmospheric air, inside a circular combustion chamber, used for ignition of the Doosan Babcock Mark III low-NOx burner type AASB, in order to adequacy of the application of the laminar flamelet concept on the numerical simulation of multidimensional non-premixed diesel flames, as well as to verify the behavior of the flow in front of the imposed boundary conditions. The simulation is based on the solution of mass, energy, momentum and chemical species conservation equations. Thermal radiation exchanges in the combustion chamber are computed through the Discrete Transfer Radiation Model (DTRM), and the gas absorption coefficient dependence on the wavelength is predicted by gray gas model. The turbulence is modeled by the standard k −ε model, and the chemical reactions by a PDF-flamelet model. The finite volume method is employed to treat the differential equations by using the commercial software Ansys CFX in the simulations. Two cases were considered with different droplet sizes, 90 μm and 50 μm. Results indicate that the flame is relatively short as expected. It was observed that large drops need more energy to evaporate, consequently removing energy from the flame and lowering the temperature of the flame. In addition, it was also observed that smaller droplets tend to have a more intense flame region, having their evaporation and oxidation closer to the fuel injection region.
Keywords
Diesel Combustion, CFD, Representative Interactive Flamelet, Droplet evaporation, flamelet
