Experimental investigation of injection spray characteristics of raw Jojoba - alcohols blends compared to diesel fuel

• Raw Jojoba oil with high viscosity exhibited inferior spray characteristics compared to diesel fuel. • The spray breakup time is affected by adding alcohol to the raw Jojoba oil. • The addition of alcohols to the Jojoba oil increased the cone diameter and volume, with DEE showing the best performance followed by Methanol- then ethanol-blended fuels. • Higher concentrations of alcohol produced superior spray features. • The addition of alcohol influenced the poor spray performance of pure Jojoba oil. An experimental investigation has been carried out to visualize the spray characteristics of raw Jojoba fuel mixed with three different alcohols in an atmospheric chamber. An injection pump for a real diesel engine has been used to inject pure Jojoba oil, its blend with three alcohols (methanol, ethanol and DEE) at 5, 10 and 15 % by volume in an atmospheric chamber. The results have been compared to the case of pure diesel fuel. A high-speed video camera has been used to visualize and store the spray injection process at the rate of 40,000 frames per second. Forty frames from injection onset with a total duration of 1 millisecond have been stored in a computer for off-line analysis. The data presented included the time-history of spray tip penetration, spray cone angle, spray cone diameter, volume, and spray tip velocity. The data also included the screen shots of the injection spray cone from the onset of injection for a duration of one millisecond for the eleven fuels tested (three raw Jojoba-alcohols at three concentrations, the raw Jojoba without alcohol and the diesel fuel). Raw Jojoba fuel exhibited the least spray tip penetration compared to diesel fuel. Spray breakup time is shortest for ethanol-blend fuels (<0.2 ms) and longest for DEE-blend fuels (greater than 0.2 ms). The addition of alcohols to the fuel mixture increases the cone diameter and cone volume, with 10 % or 15 % DEE showing the best performance (the biggest cone diameter) followed by methanol- then ethanol-blended fuels. Higher concentrations of alcohol produce higher spray volumes. The addition of alcohol significantly influences the poor spray performance of pure Jojoba oil, thus improving its prospect as a promising alternative fuel.