Experimental Investigation on Macro Spray Characteristics of Octanol-Biodiesel-Diesel Ternary Fuel Blend

This study investigates the spray characteristics of ternary blends composed of octanol, biodiesel, and diesel fuel.Experiments are conducted using six materials to examine the variation in spray characteristic and to verify and compare a previously established spray tip penetration model with a modified model. The results show that the addition of OB100(30%of octanol, 70% of biodiesel) improves the spray characteristics of the fuel. Specifically, the addition of 10% or 20% of OB100 leads to a slight increase in the spray tip penetration, average spray cone angle, maximum spray width, and the spray area of the fuel blend;however, further addition of OB100 causes a corresponding decrease in these parameters. Based on previous research, this study uses kinematic viscosity instead of dynamic viscosity and density to modify the prediction model of spray tip penetration. The modified model exhibits a better fit quality and agreement with the experimental data,making it more suitable for predicting the spray tip penetration of fuel blends compared to the Hiroyasu-Arai model.

Preparation and emission characteristics of ethanol-diesel fuel blends

The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2%) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection(DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon(HC), and carbon monoxide(CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.

Experimental Investigation of the Rail Pressure Fluctuations Correlated with Fuel Properties and Injection Settings

Injection-induced rail pressure fluctuations are proven to cause nonuniform spray development.These fluctuations are also responsible for generating lower injection pressures,to the detriment of jet penetration length and break-up timing.Despite the vast literature dealing with such issues,several aspects of rail pressure fluctuations remain unclear.Additionally,the need for compliance with the emission legislation has shed light on the potential of alternative fuels,which represent a pathway for sustainable mobility.This scenario has motivated the present study dealing with the assessment of the time history of rail pressure correlated with fuel properties.Tests have been performed using a last-generation common rail injection equipment under various injection settings,employing diesel and 2-methylfuran-diesel blend.This paper describes the research activity and aims to provide new insights into the correlation of rail pressure fluctuations with fuel properties.

Stable Combustion under Carbon Dioxide Enriched Methane Blends For Exhaust Gas Recirculation(EGR)

Exhaust gas recirculation(EGR)is one of the main techniques to enable the use of oxyfuel combustion for carbon capture and storage(CCS).However,the use of recirculated streams with elevated carbon dioxide poses different challenges.Thus,more research is required about the cumulative effects on the desirable outcomes of the combustion processes such as thermal efficiency,reduced emissions and system operability,when fuels with high CO_(2) concentration for CCS exhaust gas recirculation or biogas are used.Therefore,this study evaluates the use of various CO_(2) enriched methane blends and their response towards the formation of a great variety of structures that appear in swirling flows,which are the main mechanism for combustion control in current gas turbines systems.The study uses 100 kW acoustically excited swirl-stabilised burner to investigate the flow field response to the resultant effects of the variation in the swirl strength,excitation under isothermal condition and the corresponding effects during combustion with different fuels at various CO_(2) concentrations.Results show changes in size and location of flow structures as a result of the changes in the mean and turbulent velocities of the flow field,consequence of the imposition of different swirl and forcing conditions.Improved thermal efficiency is also observed in the system when using high swirl and forcing while the blend of CO_(2) with methane balanced the heat release fluctuation with a corresponding reduction in the acoustic amplitudes of the combustion response,suggesting that certain CO_(2) concentrations in the fuel can provide more stable flames.Concentrations between 10%to 15%CO_(2) volume show great promise for stability improvement,with the potential of using these findings in larger units that employ CCS technologies.