Visualization Experiment in a Transparent Engine With Pure and Mixed Normal Paraffin Fuels 2004-01-2018
In the previous study design of two-component normal paraffin fuel was attempted considering the components and blending ratio. Only the thermodynamic analysis of combustion and analysis of emission characteristics were performed to evaluate the design performance. In this study mixture formation behavior and combustion phenomena of pure and mixed n-paraffin fuels were investigated by direct visualization in an AVL engine with bottom view piston. The experiments included laser-illuminated high-speed photography of the fuel injection phase and combustion phase to investigate physical differences. The results obtained for the proposed fuels are compared with the results of conventional diesel fuel.
It was found that the two component normal paraffin fuels with similar thermo physical properties have very similar spray development pattern but evaporation rates are different. For a same mixture promoting component the first visible flame appears very early and the main combustion duration becomes short when the chain length of the igniting component increases. On the other hand for a same igniting component appearance of the first visible flame remains almost constant but the duration of combustion elongates with much luminous flames when the chain length of mixture promoting component increases. When the fraction of pentane in the mixture with tridecane increases the spray penetrates shorter but disperses widely. Much homogeneous charge forms, which burns with less luminous flames.