Temperature Analysis in the Combustion of the Fuel Spray in Diesel Engines

Abstract

Diesel combustion is a complex, turbulent, treedimensional, multiphase process that occurs in a hightemperature and high-pressure environment. For the Diesel combustion studies the knowledge of the temperatures in the different areas of the fuel spray after the ignition process is fundamental. Starting from the knowledge of such temperatures, it is possible to study the mechanism of the main pollutants formation such as the particulate matter and NOX. The present work proposes an extension of the phenomenological model of particulate matter emission, previously proposed by the author, now with the objective of foreseeing the temperature in some fundamental regions of the Diesel spray in combustion, like the region adjacent to the diffusion flame, where the oxidation of great part of the particulate matter occurs and where the production of the thermal NOX, which is responsible for the main part of the NOX emissions, takes place. The model validation was made through data from a single cylinder research engine, including engine data to feed the model and the temperature measurements of the spray in combustion directly inside the combustion chamber, done through Rayleigh-thermometry. The simulations showed a good correlation with the experimental data and with the most current Diesel combustion theories. The close agreement between expected and predicted values serves to further strengthen validity of the model and recommends future optimization and expansion studies.