Biofuel Pure Component Spray Characteristics at Engine-Relevant Conditions

Abstract

This paper compares the evaporating spray characteristics of biodiesel and biofuel pure component spray at engine-relevant conditions such as late-cycle postinjection and near top-dead-center injection conditions. The spray characteristics, liquid length, vapor length, and spray vapor area are predicted using an OpenFOAM CFD code. The liquid length of methyl oleate is observed to be longer under late-cycle postinjection conditions, which may lead to the impingement of liquid fuel on the combustion-chamber walls. The liquid length for methyl laurate is shorter than that of methyl oleate at high ambient temperature and density conditions. The vapor length at top-dead-center conditions for all of the biodiesel pure components is similar. The liquid length and vapor length of the straight vegetable oil pure components, triolein and trilaurin, is longer than those of their corresponding biodiesels. The liquid length, vapor length, and spray vapor area for methyl laurate are similar to those of dodecane. The liquid length of all of the pure components is found to be related to the specific energy ratio and boiling temperature of the fuel.