Droplet combustion behaviour and spray characteristics of diesel-ethanol-jatropha oil ternary fuel blends under high-pressure evaporating conditions

Abstract

This study investigates the behavior of a single droplet exposed to high-temperature ambient air and macroscopic spray characteristics of various ternary blends of diesel-ethanol-jatropha oil. The experiments on single droplet are performed at ambient pressure and high temperature. The spray experiments are performed under high-pressure and high-temperature conditions, similar to those of a diesel engine in-cylinder air at the time of fuel injection for three blends. The D50E35J15 has exhibited micro explosion behavior, D50E30J20, which has shown puffing, and D60E20J20, which has demonstrated both micro explosion and puffing during single droplet experiments, are selected for spray experiments. A constant volume spray chamber with optical access equipped with an electric heater was used to study evaporating spray characteristics of the blends at 5 MPa and 900 K. The spray experiments have shown that the ternary fuel blends have higher liquid penetration as compared to that of diesel due to the higher boiling point of jatropha oil. The variation in the spray cone angle between the different blends was found to be insignificant and within the measurement's uncertainty limits. Thus, the blends which have exhibited micro-explosion and puffing in droplet experiments, have not affected the macroscopic spray characteristics at higher ambient pressures.