Search

The present paper describes the development of sub models for combustion analysis in direct injection (DI) diesel engine fuelled with Pongamia Pinnata biodiesel-diesel blend as a fuel. In the present study, the Computational Fluid Dynamics (CFD) code FLUENT was used to model a complex combustion phenomenon in Compression Ignition (CI) engine. The experiments were performed on a single cylinder direct injection diesel engine, with a full load condition at a constant speed of 1500 rpm. Combustion parameters, such as cylinder pressure and heat release rate, were obtained from experimental data. The numerical modeling was solved by CFD code Fluent, taking into account the effect of turbulence. For modeling turbulence Renormalization Group Theory (RNG) k-ε model was used. The sub models such as droplet collision model and Taylor Analogy Breakup (TAB) model were used for spray modeling. Modeling in cylinder combustion, species transport and finite rate chemistry model were used. The results obtained from modeling were compared with experimental investigation. The peak modeling heat release rate was 30 J/s whereas the experimental peak heat release rate was 25 J/s at 364 degree CA for biodiesel. Similarly, for the diesel peak modelling, the heat release rate was 34.41 J/s whereas the experimental peak heat release rate was 27 J/s at 364 degree CA. Simulated results including the in-cylinder pressure, rate of pressure rise and heat release rate profiles have been analysed. A good agreement between the modelling and experimental data ensures the accuracy of the numerical predictions collected in this work. Including peak values of in-cylinder pressure, rate of pressure rise and heat release rate shows a good agreement between modelling and the measured data. All in all, this study demonstrates the feasibility of integrating a compact multi-component surrogate fuel mechanism with CFD to elucidate the in-cylinder combustion of biodiesel fuels. [ABSTRACT FROM AUTHOR]

This study discusses the performance and combustion characteristics of a direct injection diesel engine fueled with Jatropha methyl ester (JME). In order to determine the performance and combustion characteristics, the experiments were conducted at the constant speed mode (1500rpm) under the full load condition of the engine on a single cylinder 4-stroke CI engine. The results indicate that when the test engine is fuelled with JME, the engine performance slightly weakens, the combustion characteristics slightly change when compared to a petroleum based diesel fuel. The biodiesel causes reduction in carbon monoxide (CO), unburned hydrocarbon (HC) emissions, but they cause increases in nitrogen oxides (NOx) emissions. The useful brake power obtained is similar to diesel fuel for all loads. The oxygen content in the exhaust is more with JME blend due to the fact that fuel itself contains oxygen .The trend of oxygen emission is similar to diesel fuel for all loads. Since JME contains 11% oxygen by weight and this oxygen helps to oxidize the combustion products in the cylinder, especially in rich zones, the addition of JME decreases CO emission. Although there has not been a significant difference in NOX emissions at part load. NOx is slightly increased due to the higher combustion temperature and the presence of fuel oxygen with the blend at full load. JME as a new Biodiesel and its blends can be used in diesel engines without any engine modification. [ABSTRACT FROM AUTHOR]