Findings on droplet breakup behavior of the preheated microalgae oil jet for efficiency improvement in diesel engines

The ability to manage the liquid jet atomization and the breakup of droplets in diesel engines is becoming now one of the most important challenges of the unmodified CI engines' operations. A mature comparative analysis is performed to achieve enhancement of the injection and liquid jet breakup characteristics of microalgae oil (MAO100) at an elevated temperature of up to 80 degrees C. To obtain reliable data, the following experimental tasks were performed and qualitatively described to identify the (i) distribution of Sauter mean diameter (SMD) d(32) of fuel droplets within the temporal evolution of a fuel jet, (ii) dynamics and topology dependencies of the liquid jet atomization and droplet breakup, (iii) dynamic formation of the liquid jet structure, and (iv) character and peculiarities of liquid jet breakup. The results of the research have shown the presence of zones distinguished by very intense droplet breakup, which carried out a robust individual character that does not depend on the type and temperature of the fuel. Furthermore, the preheated MAO100 was dominant (similar to 70%) with droplets of the following size, d <= 40-50 mu m (similar to 20%) and d <= 120 mu m (similar to 50%), who were 1.2 to 1.5 smaller compared to those obtained at 20 degrees C. At t= 2 ms after injection of MAO100 (80 degrees C), the presence of droplets which radiuses exceed 500 mu m was prevented. This tendency is ideally comparable to the one for a diesel fuel that, in turn, supports the hypothesis that the physical contribution to the ignition delay and hence to the entire process of combustion could be effectively controlled by the preheating route.

Automated summary

The ability to manage the breakup of droplets and liquid jet atomization in diesel engines is a crucial challenge for unmodified CI engines. A comparative analysis of microalgae oil (MAO100) was conducted to enhance injection and liquid jet breakup characteristics at an elevated temperature. The results revealed distinct zones of intense droplet breakup, independent of fuel type and temperature. Preheated MAO100 exhibited smaller droplet sizes compared to room temperature, suggesting a controlled combustion process through preheating.