Effects of Fuel Thermo-Physical Properties on Spray Characteristics of Biodiesel Fuels

摘要

The main emphasis of this study is to examine the effects of biodiesel thermo-physical properties on the fuel spray development using CFD modelling. A complete set of 12 thermo-physical properties is estimated for PME, SME and CME. The methods employed for this as reported here are generic as the methods are dependent on the chemical compositions and temperature. Sensitivity analysis is performed by integrating the estimated fuel properties into CFD modelling. Variations in spray development such as mass of fuel evaporated and liquid and vapour axial penetration length of biodiesel fuels are found to be different from fossil diesel due to the difference in thermo-physical properties. A total of five biodiesel properties are identified to have profound impacts on fuel spray development, which are liquid density, liquid viscosity, liquid surface tension, vapour pressure and vapour diffusivity. Nevertheless, only liquid surface tension and vapour pressure are the most sensitive fuel properties to the fuel spray development. The work has provided better representation of biodiesel properties, which improve the in-cylinder CFD simulation of reacting spray jet for the fuel.