Experimental study on plasma-assisted atomization characteristics of n-Dodecane sprays

In response to the global demand for low-carbon transportation, enhancing fuel combustion efficiency is essential to reducing emissions. In high-temperature and high-pressure combustion chambers, the extremely short residence time hinders effective atomization and secondary droplet breakup, thereby limiting fuel-air mixing and increasing pollutants formation, particularly at relatively low fuel injection pressures. To address this challenge, this study introduces a plasma-assisted atomization technique for improving fuel spray characteristics. An experimental platform was established integrating shadowgraph imaging, planar Mie scattering, and particle/droplet image analysis (PDIA) to systematically evaluate the influence of plasma on n-dodecane spray. Results demonstrate that plasma increases penetration length by up to 25% and projected area by over 30%, along with a moderate increase in spray cone angle of approximately 5%to 8%, particularly under low injection pressures. At the microscopic level, plasma reduces droplet characteristic diameters, with the Sauter mean diameter (SMD) and arithmetic mean diameter ( D 10 ) decreasing by more than 15%. The droplet diameters become smaller with increasing injection pressure and plasma energy. This study eliminates the interference of aerodynamic shear by adopting opposed arc plasma matched with pure pressure atomization without auxiliary airflow, and quantitatively isolates the intrinsic atomization effect of plasma. These findings offer a promising strategy for achieving efficient fuel atomization under low injection pressure conditions, supporting the development of low-emission combustion technologies.