Kinetic modelling of combustion characteristics of biodiesel fuels

• Main Author: Chit, Wityi Oo
• Format: text
• Language: English
• Published: Animo Repository 2015
• Online Access: https://animorepository.dlsu.edu.ph/etd_doctoral/431
• Institution: De La Salle University

The biodiesel surrogate fuels are realistic kinetic tools to study the combustion of actual biodiesel fuels in diesel engines. The knowledge of fuel chemistry aids in the development of combustion model. In order to numerically simulate the diesel combustion, it is necessary to construct a compact reaction model in describing the chemical reaction. Prior to developing the model, this study investigated the ignition and combustion characteristics of various biodiesel fuels (BDFs). They are Jatropha Methyl Ester (JME), Coconut Methyl Ester (CME), Soybean Methyl Ester (SME), and Palm Methyl Ester (PME). The ignition delays and heat release rates were investigated under different ambient temperatures and pressures. The experimental results on combustion characteristics and fuel-spray development were affected by the properties of biodiesel fuels (BDFs). Based on the experimental data, all tested biodiesel fuels (BDFs) showed shorter ignition delay times around 1 ms at temperature range between 600 K and 1300 K. Among BDFs, CME exhibited the ignition delay ( ) of 3.5 ms at 900 K, which is shortest ignition delay time than the others due to its lower viscosity and lower distillation temperature. The fuel air mixing process is also related to the ignition and characteristics of fuels. Ignition delay times become shorter than the injection period for lower density and lower viscosity fuels, resulting in a very slow ignition. Potentially, these research findings may provide the information to engine manufacturers. A skeletal kinetic model of methyl decanoate (MD) and n-heptane as a biodiesel surrogate blend was developed which is simply composed of 45 chemical species and 74 reactions based on the full kinetic models containing 3787 species and 10208 reactions which have been developed by Lawrence Livermore National Laboratory (LLNL) and Knowledge-basing Utilities for Complex Reaction Systems (KUCRS) under the diesel like engine conditions. The model in this study is generated by using CHEMKIN and then it is used to prod