Numerical Analysis of Combustion Behavior in A Biodiesel Engine

• Main Authors: Po-sain Zeng, 曾柏憲
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/20559215259399448306

碩士 === 國立臺灣科技大學 === 機械工程系 === 103 === In this study, the numerical model of a Mitsubishi 4M42-4AT1 heavy duty diesel engine equipped with a turbo-charged common-rail injection system and an EGR system is constructed to simulate the combustion behaviors inside the combustion chamber. The composition of real air is adopted in setting the initial conditions of the intake air. The thermophysical and thermochemical properties of the fuels including diesel and biodiesel fuels are obtained from the Chinese Petroleum Corporation. The turbulence characteristics of the flow field inside the combustion chamber are modeled by the 2-parameter k-epsilon equations. Hardenburg’s phenomenological model is used to model the ignition delay of injected fuel. PDF model is used to simulate the flame propagation behaviors inside the combustion chamber. Experimental data including pressure and temperature histories obtained from in-situ running of the diesel engine are compared with the predicted results of numerical simulation to justify the validity of thus constructed numerical model. It is found that the numerical simulation gives decent predictions to the pressure peaks, ignition delay, and heat release rate. Numerical simulations of the same engine burning biodiesel fuels are also conducted. Lower peak pressures and shorter ignition delay than that of an engine burning D100 diesel are observed due to the lower low heating value and higher cetane number of biodiesel fuels, respectively.