Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Numerical study of the spray pattern in high pressure injected ethanol
Submission Author:
Gustavo Garcia , SP
Co-Authors:
Gustavo Garcia, GUENTHER Krieger Filho, Antonio Pacifico
Presenter: GUENTHER Krieger Filho
doi://10.26678/ABCM.COBEM2023.COB2023-0579
Abstract
The high pressure direct injection fuel technology has the potential to enhance the control of the combustion process and consequently reduce the consumption of fuel and emissions of pollutants. This control pass through the atomization process of the fuel spray. Nowadays, the injectors have multi-holes that are capable to inject the fuel in specific regions and directions of the cylinder. The studies in this area count with experimental and the CFD methodology, which have been focused mostly in gasoline and diesel fuels. The Brazilian biofuel, ethanol, has environmental and technical advantages over the gasoline. This motivated this study. As a biofuel, the ethanol is almost CO_2 neutral and the final fuel has greater heat of vaporization, resistance of detonation and faster flame speed. These characteristics are desirable in terms of the new technologies once it promotes greater thermodynamic efficiency and lower temperatures of the air/fuel mixture, resulting in greater volumetric efficiency of the engine. The numerical model is based on eulerian and lagrangian approaches to simulate the gas and liquid phase respectively. The lagrangian phase is based on the parcel concept, which statistically represents all droplets of the spray while reducing the computational cost. The Kelvin-Helmholtz model simulates the primary break-up followed by the Rayleigh-Taylor model to simulate the secondary break-up. Droplet drag and deformation, evaporation and turbulent dispersion are also taken into account. The results are validated according to experimental data collected by phase doppler interferometer (PDI) of ethanol spray injected at 100 bar by six hole commercial automotive injector that injects 16.7 miligrams of fuel during 3.5 miliseconds. The characteristics of the spray that are analyzed are the size of the droplets, their velocities and the cone angle of each injector hole. The holes position and directions were obtained from the injector’s supplier datasheet. An extensive revision of the literature was made in order to understand and tune the models parameters and the simulation results are according to the experimental data. The SMD of the droplets were between 17 μm and 43 μm while the velocities were between 10 m/s and 37 m/s in distances of 50 mm, 65 mm and 80 mm from the injector.
Keywords
High pressure, ethanol, Direct injection, CFD, PDI
